Chapter 9

SCALLOP. The common name for shells of the genus Pecten, the larger species of which were worn by pilgrims to the Holy Land in the time of the Crusades.SCALPELLUM. Leach. (A little knife or lancet.)Order, Pedunculated Cirripedes, Lam.—Descr.Flat, quadrated, acuminated, composed of thirteen valves, one dorsal, arcuated; one pair apicial, acuminated; one pair ventral; two pair lateral, small, sub-quadrate; pedicle scaly.—Obs.This genus andSmilium, are the only Pedunculated Cirripedes which have thirteen valves; in the latter genus, which we think should at any rate be united to this, the valves are somewhat differently placed, and the pedicle is said to be smooth. Fig. 35, Scalpellum vulgare. British.SCAPHA. Klein. (A boat.)Navicella, Auct.SCAPHANDER. Montf.Bullalignaria, Auct. Fig. 251.SCAPHELLA. Sw. A genus of the family "Volutinæ," Sw. thus described: "Shell smooth, almost polished; outer lip thickened internally; suture enamelled; lower plaits the smallest; apex of the spire various: 1. fusiformis. Sw. Bligh. Cat. 2. undulatus.Ex.Conch. pl. 27. 3. Junonia,Ex.Conch. pl. 33. 4. stromboides. 5. papillosa. Sw. Sow. gen." Sw. Malac. p. 318.SCAPHITES. (A boat.)Fam.Ammonacea, Lam. and Bl.—Descr.Convolute, chambered, closely related to the Ammonites, from which it differs in the last whorl being eccentrically straightened, and lengthened, and again incurved towards the extremity. Only known in a fossil state. Fig. 481, S. æqualis.SCAPHULA. Sw. A genus of "Olivinæ," Sw. thus described: "Spire very short, thick, obtuse, and not defined; aperture very wide, with only two or three oblique plaits at the base. Sw. patula,Sow.Tank. Cat. 2331. (b.)" (Sw. p. 322.)SCARABUS. Montf. (Scarabæus, a kind of beetle.)Fam.Colimacea, Lam. Auriculacea, Fer.—Descr.Oval, somewhat compressed, smooth, with slightly raised varices; spire equal in length to the aperture, pointed, consisting of numerous whorls; aperture ovate, rounded anteriorly, pointed posteriorly, modified by the last whorl; outer lip sub-reflected, with several prominent folds on the inner edge; inner lip spread over a portion of the body whorls, with several prominent folds.—Obs.The shells of this genus are found like Auriculæ, in marshy places. C. imbrium is said to have been found on the tops of mountains, by Captain Freycinet. Fig. 299*, S. imbrium.SCHIZODESMA. Gray. A genus composed of species ofMactra, Auct. with the ligament placed in an external slit. Fig. 8, M. Spengleri.SCISSURELLA. D'Orbigny. (Scissus, cut.)Fam.Turbinacea, Lam.—Descr.Sub-globose, umbilicated, with a spiral groove terminating at the margin of the outer lip in a slit; spire short; aperture oval, modified by the last whorl; outer lip sharp, with a deep slit near the spire. Recent on the coasts of Britain; fossil in the Calcaire-grossièr.—Obs.This genus, consisting of small shells, is known from Pleurotomaria by the shortness of the spire; the latter genus being trochiform. Fig. 340, S. elatior.SCOLYMUS. Sw. A genus of the family "Scolyminæ." Sw. (Turbinella) thus described: "Sub-fusiform, armed with foliated spines; spire shorter; pillar with distinct plaits in the middle." The species enumerated are, "cornigerus, pugillaris, Globulus, Rhinoceros, ceramicus, Capitellum, umbilicaris, mitis." Sw. Malac. p. 304.SCORTIMUS. Montf. A genus of microscopic Foraminifera.SCROBICULARIA. Schum. Species ofLutraria, Act. of a rounded shape.Ligula, Leach.SCROBICULATED. (Scrobiculus, a little ditch or furrow.) Having small ditches or furrows marked on the surface.SCUTELLA. Brod. (Scutellum, a little shield.)Fam.Phyllidiana, Lam.—Descr.Shaped like Ancylus, pearly within; apex posteriorly inclined, central, involute; muscular impressions two, oblong, ovate, lateral; aperture large, ovate.—Obs.This genus is intermediate between Ancylus and Patella; while in the aspect of the beak, the observer is reminded of Navicella.SCUTIBRANCHIATA. Bl. (Scutum, a shield;branchiæ, gills.) The third order of Paracephalophora Hermaphrodita, Bl. containing animals with patelliform, but not symmetrical shells, and divided into the families Otidea and Calyptracea.SCUTUM. Montf. (A shield.)Parmophorus elongatus, Lam.SECURIFORM. (Securis, an axe;forma, shape.) Hatchet-shaped.Ex.Pedum, fig. 179.SEDENTARY ANNELIDES. Lam. The third order of the class Annelides, Lam. distinguished from the two other orders by the circumstance of the animal being enveloped by a shelly tube which it never entirely leaves. The order is divided into the families Dorsalia, Maldania, Serpulacea, and Amphitrites. Fig. 1 to 13.SEA DATE. The common name forPholasDactylus in the market, given to it on account of its cylindrical shape. Fig. 35.SEGMENTINA. Flem.NautilusLacustris, Montagu. Test. Brit. Planorbis nitidus, Drap. tab. 2. Fig. 17 to 19.SEMICORDATE. Half heart-shaped.SEMIDISCOIDAL. Forming the half of a circular disc.SEMILUNAR. Half moon-shaped.SENECTUS. Humph. A genus of "Senectinæ," thus described by Swainson: "Imperforate; the base produced into a broad flat lobe, spire rather elevated and pointed; the whorls convex; aperture perfectly round; not more oblique thanHelix; inner lip entirely wanting, imperialis. Mart. 180. f. 1790. marmoratus. l. M. 448. f. 1." Sw. p. 348.SEMIPHYLLIDIANA. Lam. The second family of the order Gasteropoda, Lam. the genera of which are distinguished as follows:—

SCALLOP. The common name for shells of the genus Pecten, the larger species of which were worn by pilgrims to the Holy Land in the time of the Crusades.

SCALPELLUM. Leach. (A little knife or lancet.)Order, Pedunculated Cirripedes, Lam.—Descr.Flat, quadrated, acuminated, composed of thirteen valves, one dorsal, arcuated; one pair apicial, acuminated; one pair ventral; two pair lateral, small, sub-quadrate; pedicle scaly.—Obs.This genus andSmilium, are the only Pedunculated Cirripedes which have thirteen valves; in the latter genus, which we think should at any rate be united to this, the valves are somewhat differently placed, and the pedicle is said to be smooth. Fig. 35, Scalpellum vulgare. British.

SCAPHA. Klein. (A boat.)Navicella, Auct.

SCAPHANDER. Montf.Bullalignaria, Auct. Fig. 251.

SCAPHELLA. Sw. A genus of the family "Volutinæ," Sw. thus described: "Shell smooth, almost polished; outer lip thickened internally; suture enamelled; lower plaits the smallest; apex of the spire various: 1. fusiformis. Sw. Bligh. Cat. 2. undulatus.Ex.Conch. pl. 27. 3. Junonia,Ex.Conch. pl. 33. 4. stromboides. 5. papillosa. Sw. Sow. gen." Sw. Malac. p. 318.

SCAPHITES. (A boat.)Fam.Ammonacea, Lam. and Bl.—Descr.Convolute, chambered, closely related to the Ammonites, from which it differs in the last whorl being eccentrically straightened, and lengthened, and again incurved towards the extremity. Only known in a fossil state. Fig. 481, S. æqualis.

SCAPHULA. Sw. A genus of "Olivinæ," Sw. thus described: "Spire very short, thick, obtuse, and not defined; aperture very wide, with only two or three oblique plaits at the base. Sw. patula,Sow.Tank. Cat. 2331. (b.)" (Sw. p. 322.)

SCARABUS. Montf. (Scarabæus, a kind of beetle.)Fam.Colimacea, Lam. Auriculacea, Fer.—Descr.Oval, somewhat compressed, smooth, with slightly raised varices; spire equal in length to the aperture, pointed, consisting of numerous whorls; aperture ovate, rounded anteriorly, pointed posteriorly, modified by the last whorl; outer lip sub-reflected, with several prominent folds on the inner edge; inner lip spread over a portion of the body whorls, with several prominent folds.—Obs.The shells of this genus are found like Auriculæ, in marshy places. C. imbrium is said to have been found on the tops of mountains, by Captain Freycinet. Fig. 299*, S. imbrium.

SCHIZODESMA. Gray. A genus composed of species ofMactra, Auct. with the ligament placed in an external slit. Fig. 8, M. Spengleri.

SCISSURELLA. D'Orbigny. (Scissus, cut.)Fam.Turbinacea, Lam.—Descr.Sub-globose, umbilicated, with a spiral groove terminating at the margin of the outer lip in a slit; spire short; aperture oval, modified by the last whorl; outer lip sharp, with a deep slit near the spire. Recent on the coasts of Britain; fossil in the Calcaire-grossièr.—Obs.This genus, consisting of small shells, is known from Pleurotomaria by the shortness of the spire; the latter genus being trochiform. Fig. 340, S. elatior.

SCOLYMUS. Sw. A genus of the family "Scolyminæ." Sw. (Turbinella) thus described: "Sub-fusiform, armed with foliated spines; spire shorter; pillar with distinct plaits in the middle." The species enumerated are, "cornigerus, pugillaris, Globulus, Rhinoceros, ceramicus, Capitellum, umbilicaris, mitis." Sw. Malac. p. 304.

SCORTIMUS. Montf. A genus of microscopic Foraminifera.

SCROBICULARIA. Schum. Species ofLutraria, Act. of a rounded shape.Ligula, Leach.

SCROBICULATED. (Scrobiculus, a little ditch or furrow.) Having small ditches or furrows marked on the surface.

SCUTELLA. Brod. (Scutellum, a little shield.)Fam.Phyllidiana, Lam.—Descr.Shaped like Ancylus, pearly within; apex posteriorly inclined, central, involute; muscular impressions two, oblong, ovate, lateral; aperture large, ovate.—Obs.This genus is intermediate between Ancylus and Patella; while in the aspect of the beak, the observer is reminded of Navicella.

SCUTIBRANCHIATA. Bl. (Scutum, a shield;branchiæ, gills.) The third order of Paracephalophora Hermaphrodita, Bl. containing animals with patelliform, but not symmetrical shells, and divided into the families Otidea and Calyptracea.

SCUTUM. Montf. (A shield.)Parmophorus elongatus, Lam.

SECURIFORM. (Securis, an axe;forma, shape.) Hatchet-shaped.Ex.Pedum, fig. 179.

SEDENTARY ANNELIDES. Lam. The third order of the class Annelides, Lam. distinguished from the two other orders by the circumstance of the animal being enveloped by a shelly tube which it never entirely leaves. The order is divided into the families Dorsalia, Maldania, Serpulacea, and Amphitrites. Fig. 1 to 13.

SEA DATE. The common name forPholasDactylus in the market, given to it on account of its cylindrical shape. Fig. 35.

SEGMENTINA. Flem.NautilusLacustris, Montagu. Test. Brit. Planorbis nitidus, Drap. tab. 2. Fig. 17 to 19.

SEMICORDATE. Half heart-shaped.

SEMIDISCOIDAL. Forming the half of a circular disc.

SEMILUNAR. Half moon-shaped.

SENECTUS. Humph. A genus of "Senectinæ," thus described by Swainson: "Imperforate; the base produced into a broad flat lobe, spire rather elevated and pointed; the whorls convex; aperture perfectly round; not more oblique thanHelix; inner lip entirely wanting, imperialis. Mart. 180. f. 1790. marmoratus. l. M. 448. f. 1." Sw. p. 348.

SEMIPHYLLIDIANA. Lam. The second family of the order Gasteropoda, Lam. the genera of which are distinguished as follows:—

1.Umbrella, round, flat; apex central, muscular impression not interrupted. Fig. 233.2.Pleurobranchus, apex lateral, sub-spiral. Fig. 232.

1.Umbrella, round, flat; apex central, muscular impression not interrupted. Fig. 233.

2.Pleurobranchus, apex lateral, sub-spiral. Fig. 232.

SENOCLITA. Schum.Cineras, Leach.SEPTARIA. Lam. SeeTeredo.SEPTUM. (Lat.) An enclosure, applied to the thin plate of Crepidula, fig. 239; also to the plates dividing the chambers of multilocular shells.SERAPHS. Montf.Terebellumconvolutum, Lam. Fig. 451.SERPULA. Auct. (A little serpent.)Fam.Surpulacea, Lam.—Descr.Tubular, narrow, pointed at the apex, gradually widening towards the aperture, attached irregularly, sometimes spirally, twisted, imbricated; keeled or plain; aperture generally round, with the edge simple, or angulated by the termination of external ribs or keels.—Obs.This description is intended to include the genera Serpula, Spirorbis, Vermilia, Galeolaria, &c. The Serpulæ abound in all seas, on rocky shores, at any time covered by water, attached to any kind of marine substance, whether moveable or stationary. The fossil species occur in almost all tertiary strata. Fig. 4 to 7.SERPULACEA. Lam. The fourth family of the order Sedentary Annelides, Lam. containing the following genera of tubular, irregular shells.

SENOCLITA. Schum.Cineras, Leach.

SEPTARIA. Lam. SeeTeredo.

SEPTUM. (Lat.) An enclosure, applied to the thin plate of Crepidula, fig. 239; also to the plates dividing the chambers of multilocular shells.

SERAPHS. Montf.Terebellumconvolutum, Lam. Fig. 451.

SERPULA. Auct. (A little serpent.)Fam.Surpulacea, Lam.—Descr.Tubular, narrow, pointed at the apex, gradually widening towards the aperture, attached irregularly, sometimes spirally, twisted, imbricated; keeled or plain; aperture generally round, with the edge simple, or angulated by the termination of external ribs or keels.—Obs.This description is intended to include the genera Serpula, Spirorbis, Vermilia, Galeolaria, &c. The Serpulæ abound in all seas, on rocky shores, at any time covered by water, attached to any kind of marine substance, whether moveable or stationary. The fossil species occur in almost all tertiary strata. Fig. 4 to 7.

SERPULACEA. Lam. The fourth family of the order Sedentary Annelides, Lam. containing the following genera of tubular, irregular shells.

1.Serpula, attached by a small portion of the shell. Fig. 4.2.Spirorbis, attached by the whole length, coiled. Fig. 5.3. Galeolaria, with the open extremity raised, and the aperture tongue-shaped. Fig. 6.4.Vermilia, attached by the whole length, straight or waved. Fig. 7.5.Spiroglyphus, which hollows a bed in the body to which it is attached. Fig. 8.5.Sowerby. (Genera of Shells, published at 50, Great Russell Street, Bloomsbury,) gives satisfactory reasons for re-uniting the whole of the preceding under the nameSerpula.6.Magilus, which burrows in coral; outer lip reflected. Fig. 9 to 10.7.Leptoconchus, outer lip reflected. Fig. 11.8.Stylifer, spiral, thin, globular, living in Starfish. Fig. 12, 13.5.The three last genera should certainly find some other place in the system.

1.Serpula, attached by a small portion of the shell. Fig. 4.

2.Spirorbis, attached by the whole length, coiled. Fig. 5.

3. Galeolaria, with the open extremity raised, and the aperture tongue-shaped. Fig. 6.

4.Vermilia, attached by the whole length, straight or waved. Fig. 7.

5.Spiroglyphus, which hollows a bed in the body to which it is attached. Fig. 8.

5.Sowerby. (Genera of Shells, published at 50, Great Russell Street, Bloomsbury,) gives satisfactory reasons for re-uniting the whole of the preceding under the nameSerpula.

6.Magilus, which burrows in coral; outer lip reflected. Fig. 9 to 10.

7.Leptoconchus, outer lip reflected. Fig. 11.

8.Stylifer, spiral, thin, globular, living in Starfish. Fig. 12, 13.

5.The three last genera should certainly find some other place in the system.

SESSILE CIRRIPEDES. Lam. (Sessilis, low, dwarfish.) An order of Cirripedes, consisting of those which are attached by the base of the shells, containing the genera Tubicinella, Balanus, Coronula, Acasta, Pyrgoma, Creusia. To which may be added some other genera enumerated in explanation of figures 14 to 33. The shells of the Sessile Cirripedes consist of two different sets of valves: 1st. Theparietalvalves, or pieces arranged in a circle, side by side, around the body of the animal, (an arrangement designatedcoronularby De Blainville.) 2nd. Theopercularvalves, or pieces placed so as to enclose the aperture. Between those opercular valves the ciliæ protrude which characterize the class. Besides these two sets of valves, there is generally a shelly plate, serving as a sort of foundation to the rest. The Sessile Cirripedes may be thus arranged.

SESSILE CIRRIPEDES. Lam. (Sessilis, low, dwarfish.) An order of Cirripedes, consisting of those which are attached by the base of the shells, containing the genera Tubicinella, Balanus, Coronula, Acasta, Pyrgoma, Creusia. To which may be added some other genera enumerated in explanation of figures 14 to 33. The shells of the Sessile Cirripedes consist of two different sets of valves: 1st. Theparietalvalves, or pieces arranged in a circle, side by side, around the body of the animal, (an arrangement designatedcoronularby De Blainville.) 2nd. Theopercularvalves, or pieces placed so as to enclose the aperture. Between those opercular valves the ciliæ protrude which characterize the class. Besides these two sets of valves, there is generally a shelly plate, serving as a sort of foundation to the rest. The Sessile Cirripedes may be thus arranged.

1.Tubicinella.Six parietal valves, tube-shaped, opercular valves perpendicular. Fig. 14.2.Coronula.Six parietal valves, opercular valves horizontal. Fig. 15, 16, 17, 18.2.These two genera fix themselves in the skin of the Whale. The latter has been divided into the genera Chelonobia, Cetopirus, Diadema, and Chthalamus.3.Platylepas.Valves divided, each having a prominent internal plate. Fig. 19.4.Clitia.Parietal valves four, opercular valves two, valves dove-tailed into each other. Fig. 20.5.Elmineus.Parietal valves four, opercular valves four. Fig. 22.6.Conia.Parietal valves four, thick and porous at the base. Fig. 21.7.Octomeris.Parietal valves eight. Fig. 24.8.Catophragmus.Parietal valves numerous, irregular. Fig. 23.9.Balanus.Parietal valves six; opercular valves four, placed against each other conically in pairs. This genus has been divided into Acasta, Conoplea, Chirona, and Balanus. Fig. 25, 26, 27.10.Creusia.Parietal valves four, supported on the edge of a funnel-shaped cavity. Fig. 28.11.Pyrgoma.Paries simple, supported on a cavity. This genus has been divided into the genera Nobia, Savignium, Pyrgoma, Adna, Megatrema, and Daracia. Fig. 29 to 33.

1.Tubicinella.Six parietal valves, tube-shaped, opercular valves perpendicular. Fig. 14.

2.Coronula.Six parietal valves, opercular valves horizontal. Fig. 15, 16, 17, 18.

2.These two genera fix themselves in the skin of the Whale. The latter has been divided into the genera Chelonobia, Cetopirus, Diadema, and Chthalamus.

3.Platylepas.Valves divided, each having a prominent internal plate. Fig. 19.

4.Clitia.Parietal valves four, opercular valves two, valves dove-tailed into each other. Fig. 20.

5.Elmineus.Parietal valves four, opercular valves four. Fig. 22.

6.Conia.Parietal valves four, thick and porous at the base. Fig. 21.

7.Octomeris.Parietal valves eight. Fig. 24.

8.Catophragmus.Parietal valves numerous, irregular. Fig. 23.

9.Balanus.Parietal valves six; opercular valves four, placed against each other conically in pairs. This genus has been divided into Acasta, Conoplea, Chirona, and Balanus. Fig. 25, 26, 27.

10.Creusia.Parietal valves four, supported on the edge of a funnel-shaped cavity. Fig. 28.

11.Pyrgoma.Paries simple, supported on a cavity. This genus has been divided into the genera Nobia, Savignium, Pyrgoma, Adna, Megatrema, and Daracia. Fig. 29 to 33.

SETIFEROUS. Hairy.SHANK SHELL. The vulgar name for the shell designated Murex Rapa. It is used in Ceylon for ornamental purposes.SIDEROLITES. Montf. A genus of microscopic Foraminifera.SIGARETUS. Lam.Fam.Macrostomata, Lam.—Descr.Suborbicular, oblique, haliotoid, thick; spire depressed, consisting of two or three rapidly increasing whorls; aperture wide, entire, modified by the last whorl, the width exceeding the length; columella tortuous; inner lip spread thinly over part of the body whorl; epidermis thin.—Obs.This genus is distinguished from Natica, by the width of the aperture, and the absence of the umbilical callosity. It may be known from Stomatia, and Stomatella, by the texture, which in Sigaretus, is never pearly as in Stomatia, the former being partly an internal shell. Fig. 334, S. concavus. Mostly brought from tropical climates.SILIQUA. Megerle. (A husk, or pod.)Leguminaria, Schum. A genus composed of species ofSolen, Auct. which have an internal rib. Fig. 51, Solen radiatus.SILIQUARIA. Brug.Fam.Cricostomata, Bl. Dorsalia, Lam.—Descr.Tubular, rugose, spiral near the apex, irregularly twisted near the aperture, with a longitudinal fissure radiating from the apex, and proceeding through all the whorls and sinuosities of the tube.—Obs.This genus was included in Serpula by Linnæus, from which, however, it is distinguished by the longitudinal slit, fig. 1. S. anguina. The recent species are found in the sponges with siliceous spiculæ, in the Mediterranean; the fossils in tertiary beds.SIMPLE. (Simplex, lat.) Single, entire, uninterrupted, undivided.SIMPLEGAS. Mont. 1, 83. (Simplex, simple;γαστηρ,gaster, belly.) A genus described by De Blainville, as being discoidal, and having the spire uncovered likeAmmonites, but having the chambers divided, by simple septa, like Nautilus.—Obs.The septa of the shell named Simplegas by De Montfort, are evidently sinuous, according to his figure. Fig. 475, S. sulcata.SINISTRAL. (Sinister, left.) On the left side. A sinistral shell is areversedone. The sinistral valve of a bivalve shell may be known, by placing the shell, with its ligamentary or posterior part towards the observer; the sides of the shell will then correspond with his right and left side.SINUOUS. Winding, serpentine. The septa of Ammonites are sinuous. The muscular impression of the mantle, or palleal impression of some bivalve shells, is sinuated near the posterior muscular impression.SINUS. (Sinus, a winding, or bay.) A winding or tortuous excavation. The sinus in the outer lip of Strombus, fig. 406; and that in the muscular impression of Venus, will be indicated by the letters.SIPHON. (Σιφον, siphon.) A pipe, or tube. A shelly tube passing through the septa of chambered shells. It is said to bedorsal,central, orventral, according to its situation near the outer, or inner parts of the whorl. See Introduction.SIPHONAL SCAR. The name applied by Mr. Gray, to the opening or winding sinus in the palleal impression of a bivalve shell, in the place where the siphonal tube of the animal passes.SIPHONARIA. Sow. (Σιφον, siphon.)Fam.Phyllidiana, Lam. Patelloidea, Bl.—Descr.Patelliform, depressed, inclining to oval, ribbed; apex nearly central, obliquely inclining towards the posterior margin; muscular impression partly encircling the central disc, but interrupted in front, where the head of the animal reposes, and at the side by a siphon, or canal passing from the apex to the margin.—Obs.This siphon, which is in some species very distinct, serves to distinguish this genus from Patella. S. Sipho, fig. 231*.SIPHONOBRANCHIATA. Bl. (Siphon, andBranchiæ, gills.) The first order of Paracephalophora Dioica, Bl. divided into the families Siphonostomata, Entomostomata, and Angiostomata.SIPHONOSTOMA. Guild. A sub-genus of Pupa, consisting of several elongated species, which have the aperture detached from the whorls; such as P. costata, and fasciata.SIPHONOSTOMATA. Bl. (Σιφον,siphon;στομα,stoma, mouth.) The first family of Siphonobranchiata, Bl. the shells of which are extremely variable in form, but always have a canal or notch at the anterior extremity of the aperture. This family partly answers to the Canalifera of Lamarck and the genus Murex in the system of Linnæus. It contains the genera Pleurotoma, Rostellaria, Fusus, Pyrula, Fasciolaria, Turbinella, Columbella, Triton, Murex, Ranella, and Struthiolaria.SIPHUNCLE. (Siphunculus.) A small siphon.SISTRUM. Montf.Ricinula, Auct. fig. 413.SKENEA.Flem.A genus including some species ofEuomphalusandCirrus.SMILUM. Leach.Fam.Pedunculated Cirripedes.—Descr.Thirteen pieces, ten of which are in pairs, lateral, subtriangular; one posterior dorsal, linear; all smooth; peduncle hairy.—Obs.This genus is distinguished from Pentelasmis, by the number of its valves, and from Scalpellum, by the hairy peduncle. S. Peronii, fig. 36.SNAIL. The common garden Snail, so destructive to our vegetables, belongs to the genus Helix. The water snail, found in ponds, is Planorbis.SOL. Humph. A genus consisting of several species of the genus Trochus, and corresponding with the sub-genus Tubicanthus, Sw. Malac. Fig. 349.SOLARIUM. Auct. (A terrace, or gallery.)Fam.Turbinacea, Lam. Goniostomata, Bl.—Descr.Discoidal beneath, conical above, with a wide umbilicus, the spiral margin of which is angulated and crenulated; aperture trapezoidal; peritreme thin, sharp; columella straight; operculum horny, subspiral.—Obs.The Solarium Perspectivum, is commonly called the Staircase Trochus, from the angulated edges of the whorls being seen through the umbilicus, which reaches to the apex, and presents the appearance of a winding gallery. The species are not numerous, they belong to tropical climates. A few fossil species occur in the tertiary formations. Fig. 353, S. Perspectivum.SOLDANIA. D'Orb. A genus of microscopic Foraminifera.SOLEN. Auct. (A kind of shell-fish, Plin.)Fam.Solenacea, Lam. Pyloridea, Bl.—Descr.Bivalve, transversely elongated, sub-cylindrical, equivalve, very inequilateral, gaping at both extremities, umbones terminal, close to the anterior extremity; hinge linear, with several small cardinal teeth, and a long, external ligament; muscular impressions distant, anterior tongue-shaped, placed behind the cardinal teeth, posterior irregular, sub-ovate; palleal impression long, bilobed posteriorly.—Obs.The above description of the genus Solen, is framed so as to admit only those species which are commonly called Razor Shells, with the umbones terminal, and the anterior muscular impression behind them. They are found buried deep in the sand, in a perpendicular position, their situation being pointed out by a dimple, on the surface. They are abundant in temperate climates. Some of the Lamarckian Solenes will be found in the genus Solenocurtus, Bl. Fig. 60, 61.SOLENACEA. Lam. A family of the order Conchifera, Dimyaria Lam. The shells belonging to it are described as transversely elongated, destitute of accessary pieces, gaping only at the lateral extremities; ligament external.—The genera may be thus distinguished.

SETIFEROUS. Hairy.

SHANK SHELL. The vulgar name for the shell designated Murex Rapa. It is used in Ceylon for ornamental purposes.

SIDEROLITES. Montf. A genus of microscopic Foraminifera.

SIGARETUS. Lam.Fam.Macrostomata, Lam.—Descr.Suborbicular, oblique, haliotoid, thick; spire depressed, consisting of two or three rapidly increasing whorls; aperture wide, entire, modified by the last whorl, the width exceeding the length; columella tortuous; inner lip spread thinly over part of the body whorl; epidermis thin.—Obs.This genus is distinguished from Natica, by the width of the aperture, and the absence of the umbilical callosity. It may be known from Stomatia, and Stomatella, by the texture, which in Sigaretus, is never pearly as in Stomatia, the former being partly an internal shell. Fig. 334, S. concavus. Mostly brought from tropical climates.

SILIQUA. Megerle. (A husk, or pod.)Leguminaria, Schum. A genus composed of species ofSolen, Auct. which have an internal rib. Fig. 51, Solen radiatus.

SILIQUARIA. Brug.Fam.Cricostomata, Bl. Dorsalia, Lam.—Descr.Tubular, rugose, spiral near the apex, irregularly twisted near the aperture, with a longitudinal fissure radiating from the apex, and proceeding through all the whorls and sinuosities of the tube.—Obs.This genus was included in Serpula by Linnæus, from which, however, it is distinguished by the longitudinal slit, fig. 1. S. anguina. The recent species are found in the sponges with siliceous spiculæ, in the Mediterranean; the fossils in tertiary beds.

SIMPLE. (Simplex, lat.) Single, entire, uninterrupted, undivided.

SIMPLEGAS. Mont. 1, 83. (Simplex, simple;γαστηρ,gaster, belly.) A genus described by De Blainville, as being discoidal, and having the spire uncovered likeAmmonites, but having the chambers divided, by simple septa, like Nautilus.—Obs.The septa of the shell named Simplegas by De Montfort, are evidently sinuous, according to his figure. Fig. 475, S. sulcata.

SINISTRAL. (Sinister, left.) On the left side. A sinistral shell is areversedone. The sinistral valve of a bivalve shell may be known, by placing the shell, with its ligamentary or posterior part towards the observer; the sides of the shell will then correspond with his right and left side.

SINUOUS. Winding, serpentine. The septa of Ammonites are sinuous. The muscular impression of the mantle, or palleal impression of some bivalve shells, is sinuated near the posterior muscular impression.

SINUS. (Sinus, a winding, or bay.) A winding or tortuous excavation. The sinus in the outer lip of Strombus, fig. 406; and that in the muscular impression of Venus, will be indicated by the letters.

SIPHON. (Σιφον, siphon.) A pipe, or tube. A shelly tube passing through the septa of chambered shells. It is said to bedorsal,central, orventral, according to its situation near the outer, or inner parts of the whorl. See Introduction.

SIPHONAL SCAR. The name applied by Mr. Gray, to the opening or winding sinus in the palleal impression of a bivalve shell, in the place where the siphonal tube of the animal passes.

SIPHONARIA. Sow. (Σιφον, siphon.)Fam.Phyllidiana, Lam. Patelloidea, Bl.—Descr.Patelliform, depressed, inclining to oval, ribbed; apex nearly central, obliquely inclining towards the posterior margin; muscular impression partly encircling the central disc, but interrupted in front, where the head of the animal reposes, and at the side by a siphon, or canal passing from the apex to the margin.—Obs.This siphon, which is in some species very distinct, serves to distinguish this genus from Patella. S. Sipho, fig. 231*.

SIPHONOBRANCHIATA. Bl. (Siphon, andBranchiæ, gills.) The first order of Paracephalophora Dioica, Bl. divided into the families Siphonostomata, Entomostomata, and Angiostomata.

SIPHONOSTOMA. Guild. A sub-genus of Pupa, consisting of several elongated species, which have the aperture detached from the whorls; such as P. costata, and fasciata.

SIPHONOSTOMATA. Bl. (Σιφον,siphon;στομα,stoma, mouth.) The first family of Siphonobranchiata, Bl. the shells of which are extremely variable in form, but always have a canal or notch at the anterior extremity of the aperture. This family partly answers to the Canalifera of Lamarck and the genus Murex in the system of Linnæus. It contains the genera Pleurotoma, Rostellaria, Fusus, Pyrula, Fasciolaria, Turbinella, Columbella, Triton, Murex, Ranella, and Struthiolaria.

SIPHUNCLE. (Siphunculus.) A small siphon.

SISTRUM. Montf.Ricinula, Auct. fig. 413.

SKENEA.Flem.A genus including some species ofEuomphalusandCirrus.

SMILUM. Leach.Fam.Pedunculated Cirripedes.—Descr.Thirteen pieces, ten of which are in pairs, lateral, subtriangular; one posterior dorsal, linear; all smooth; peduncle hairy.—Obs.This genus is distinguished from Pentelasmis, by the number of its valves, and from Scalpellum, by the hairy peduncle. S. Peronii, fig. 36.

SNAIL. The common garden Snail, so destructive to our vegetables, belongs to the genus Helix. The water snail, found in ponds, is Planorbis.

SOL. Humph. A genus consisting of several species of the genus Trochus, and corresponding with the sub-genus Tubicanthus, Sw. Malac. Fig. 349.

SOLARIUM. Auct. (A terrace, or gallery.)Fam.Turbinacea, Lam. Goniostomata, Bl.—Descr.Discoidal beneath, conical above, with a wide umbilicus, the spiral margin of which is angulated and crenulated; aperture trapezoidal; peritreme thin, sharp; columella straight; operculum horny, subspiral.—Obs.The Solarium Perspectivum, is commonly called the Staircase Trochus, from the angulated edges of the whorls being seen through the umbilicus, which reaches to the apex, and presents the appearance of a winding gallery. The species are not numerous, they belong to tropical climates. A few fossil species occur in the tertiary formations. Fig. 353, S. Perspectivum.

SOLDANIA. D'Orb. A genus of microscopic Foraminifera.

SOLEN. Auct. (A kind of shell-fish, Plin.)Fam.Solenacea, Lam. Pyloridea, Bl.—Descr.Bivalve, transversely elongated, sub-cylindrical, equivalve, very inequilateral, gaping at both extremities, umbones terminal, close to the anterior extremity; hinge linear, with several small cardinal teeth, and a long, external ligament; muscular impressions distant, anterior tongue-shaped, placed behind the cardinal teeth, posterior irregular, sub-ovate; palleal impression long, bilobed posteriorly.—Obs.The above description of the genus Solen, is framed so as to admit only those species which are commonly called Razor Shells, with the umbones terminal, and the anterior muscular impression behind them. They are found buried deep in the sand, in a perpendicular position, their situation being pointed out by a dimple, on the surface. They are abundant in temperate climates. Some of the Lamarckian Solenes will be found in the genus Solenocurtus, Bl. Fig. 60, 61.

SOLENACEA. Lam. A family of the order Conchifera, Dimyaria Lam. The shells belonging to it are described as transversely elongated, destitute of accessary pieces, gaping only at the lateral extremities; ligament external.—The genera may be thus distinguished.

1.Solen.Razor shells, truncated at the extremities. Fig. 60.2.Panopæa.Broad, with prominent tooth. Fig. 65, 66.3.Solenocurtus.Rounded at the extremities, with internal bar. Fig. 61.4.Solenimya.No teeth, epidermis over-reaching the shell. Fig. 68.5.Glycimeris.Thick, fulcrum of the ligament prominent. Fig. 67.6.Lepton.Flat, scale-shaped. Fig 62.7.Novaculina.Umbones nearly central; covered by a thin epidermis. Fig. 63.8.Glauconome.Oval, margins close. Fig. 64.

1.Solen.Razor shells, truncated at the extremities. Fig. 60.

2.Panopæa.Broad, with prominent tooth. Fig. 65, 66.

3.Solenocurtus.Rounded at the extremities, with internal bar. Fig. 61.

4.Solenimya.No teeth, epidermis over-reaching the shell. Fig. 68.

5.Glycimeris.Thick, fulcrum of the ligament prominent. Fig. 67.

6.Lepton.Flat, scale-shaped. Fig 62.

7.Novaculina.Umbones nearly central; covered by a thin epidermis. Fig. 63.

8.Glauconome.Oval, margins close. Fig. 64.

SOLENELLA. Sow. (Solen.)Fam.Arcacea, Lam.—Descr.Oval, equivalve, subequilateral, compressed, covered with a thin, shining, olive-green epidermis; hinge with three or four anterior, and numerous sharp posterior lateral teeth, arranged in a straight line; muscular impressions two, lateral; palleal impression with a large sinus; ligament external, prominent, elongated.—Obs.This genus partakes of the characters of the genus Nucula, and of the family Solenacea. A few specimens of the only species known (S. Norrisii, fig. 138.) were dredged by Mr. Cuming at Valparaiso.SOLENIMYA. Lam. (Solen and Mya.)Fam.Mactracea, Lau. Pyloridea, Bl.—Descr.Equivalve, inequilateral, transversely oblong, rounded at the extremities with the umbones near the posterior side, covered with a shining brown epidermis extending beyond the edges of the shell; hinge without teeth; ligament partly internal, placed in the margin of an oblique, flattish, posterior rib; muscular impressions two, distant, lateral. From the Mediterranean, Australian, and Atlantic Oceans.—Obs.Solenimya differs from Solenocurtus and the true Solens, in having the posterior side of the shell the shortest; in the internal ligament; and in being destitute of teeth. It resembles Glycimeris, but is not incrassated. Fig. 68, Solenimya radiata.SOLENOCURTUS. Bl. (Solenandcurtus, short.)Fam.Pyloridea, Bl. Solenacea, Lam.—Descr.Oval, elongated, equivalve, sub-equilateral, with the edges nearly straight and parallel, and the extremities rather truncated; umbones not very prominent, sub-central; hinge with or without two or three rudimentary cardinal teeth; ligament prominent, placed upon thick callosities; muscular impressions two, distant, rounded; palleal impression straight, with a deep sinus. East Indies—Obs.Distinguished from the true Solenes by the central position of the umbones and an internal bar reaching partly across the shell.SOLETELLINA. Bl.Sanguinolariaradiata. S. Diphos, f. 99. S. livida of Sowerby, and similar species, are placed together in this genus.SPATHA. Lea. A sub-genus ofIridinæ, consisting of I. rubens and I. nilotica, which have not distinctly crenulated margins. Spatha solenoides, of Lea, is the genus Mycetopus D'Orbigny. Fig. 151.SPHÆNIA. Turt. A genus consisting of a small species resembling Saxicava, in general appearance, but having a spoon-shaped process on the hinge of one valve. S. Binghamii, Fig. 96.SPHÆROIDINA. D'Orb. A genus of microscopic Foraminifera.SPHÆRULACEA. Bl. The first family of Cellulacea consisting of the following genera of microscopic Foraminifera: Miliola, Melonia, Saracenaria, Textularia.SPHÆRULACEA. Lam. The fourth family of Cephalopoda, Lam. described as multilocular, globular, sphærical, or oval, with the whorls enveloping each other; some of them have a particular internal cavity, and are composed of a series of elongated, straight and contiguous chambers which altogether form a covering for the internal cavity. This family contains the genera Miliola, Gyrogona and Melonia.SPHÆRULITES. Lam. (Sphæra, a sphere.)Fam.Rudistes, Lam. and Bl.—Descr.Orbicular, inequivalve, irregularly foliated outside; lower valve cup-shaped, depressed; upper valve nearly flat, like an operculum.—Obs.These fossils are not regarded as shells by all conchologists. S. foliacea, Fig. 193.SPHINCTERULUS. Montf.Lenticulina, Bl. A genus of microscopic Foraminifera.SPINES. (Spina, a thorn.) Thin, pointed spikes.SPINOSE. (Spinosus.) Having spines or elevated points, as Neritina spinosa. Fig. 325.SPIRAL. (Spira, a spire.) Revolving outwards from a central apex or nucleus, like the spring of a watch. A shell or an operculum, may be spiral, without being produced into a pyramid. Bands of colour, striæ, grooves, &c. commencing from the nucleus and following the volutions of the shell, are described by the above word.SPIRAMILLA. Bl. A genus of Serpulacea, differing from other Serpulæ principally in the characters of the animal.SPIRATELLA. Bl.Limacinea, Lam. Fig. 224.SPIRE. (Spira.) The cone or pyramid produced in a non-symmetrical univalve by its oblique revolution downwards from the apex or nucleus. The spire, in descriptions, includes all the volutions above the aperture. See Introduction.SPIRIFER. Sow. (Spira, a spire;fero, to bear.)Order, Brachiopoda, Lam.—Descr.Transverse, equilateral; hinge linear, straight, widely extended on both sides of the umbones, which are separated by a flat area in the upper and larger valve; this area is divided in the centre by a triangular pit for the passage of the byssus; interior with two spirally convolute appendages.—Obs.This genus, which is only known in a fossil state, is distinguished from Terebratula externally, by the flat area in one valve, internally, by the singular spiral process from which the above name is derived. Fig. 214, 215. Most of the species belong to the mountain or carboniferous limestone.SPIROGLYPHUS. Daud. A genus consisting of a species of SerpulaAuct.which makes a groove for itself in the surface of shells. Serpula spirorbis, var. Dillwyn. Fig. 8.SPIROLINA. Lam. A genus of microscopic Foraminifera.SPIROLOCULINA. D'Orb. A genus of microscopic Foraminifera.SPIRORBIS. Lam. A genus composed of species ofSerpula, Auct. which are coiled round in a spiral disc like a snake at rest. S. nautiloides, fig. 5, is the common little white shell, found upon the shell of lobsters.SPIRULA. (Spira, a winding compass.)Fam.Lituolata, Lam. Lituacea, Bl.—Descr.Convolute, smooth, symmetrical, discoid, with parallel unconnected whorls, divided into numerous chambers by transverse septa; siphon continuous.—Obs.This pretty little shell is partly internal, only a part of it being visible when on the animal. Fig. 471.SPISULA. Gray. A genus composed ofMactrafragilis, and other similar species, which have the ligament sub-external, marginal, not separate from the cartilage; with the posterior lateral teeth double in one valve, and single in the other. M. fragilis, fig. 80, is the species figured for Spisula in Mr. Gray's paper on the Mactradæ, in the second series of Loudon's Magazine of Natural History. We have since learned, however, that it was figured there by mistake, not having been intended for a Spisula, but belonging more properly to the genus Mactra, as defined by Mr. Gray, whose description of Spisula, is as follows:—"Shell ovate, trigonal, sub-angular at each end. Hinge and lateral teeth as in Mactra, but hinge of left tooth small. Siphonal inflexion ovate." The principal difference between Spisula and Mactra is, that the ligament is not separated from the cartilage in the former.SPONDYLUS. Auct. (A shell-fish, Ancients.)Fam.Pectenides, Lam. Sub-ostracea, Bl.—Descr.Inequivalve, sub-equilateral, irregularly foliaceous and spinose, auriculated, denticulated at the margins, attached by the lower and deeper valve; hinge rectilinear, with two prominent teeth in each valve, locking into corresponding cavities in the opposite valve; umbones separated by a broad, elongated, triangular disc in the lower valve; ligament contained in a groove, dividing the triangular area in the centre; muscular impressions one in each valve, sub-central, sub-orbicular. The Mediterranean, East and West Indies, and China, produce Spondyli most abundantly.—Obs.This genus is remarkable for the richness and beauty of the spines and foliations, which adorn the external surface of most of the species, the splendid colours by which many of them are varied, and the natural groupings formed by their attachment to each other. Fig. 177, and Frontispiece.SPORULUS. Montf. A genus of microscopic Foraminifera.SQUAMOSE. (Squama, a scale.) Scaly, covered with scales, as the pedicle of Pollicipes Mitellus, fig. 37*.STENOPUS. Guild. (Στενος, narrow,πους, foot.) A genus nearly "allied to the Linnæan Helices, from all of which it differs in the curious contraction of the pedal disc, and the caudal tentaculum furnished with a gland beneath." The shell is described as heliciform, umbilicated, transparent, with the aperture transverse. The two species described are Stenopus cruentatus and lividus; they are both from the Caribbæan Islands, Guild. Zool. Journ. xii. p. 528, tab. 15, f. 1 to 5.STOMATELLA. Lam. SeeStomatia.STOMATIA. Auct. (στομα,stoma, mouth.)Fam.Macrostomata, Lam.—Descr.Sub-orbicular, oblong, auriform, variegated without, iridescent within; spire depressed; aperture entire, very wide, oblique; peritreme uninterrupted.Obs.This genus is known from Haliotis by being destitute of the series of holes; is distinguished from Sigaretus by the substance of the shell, the latter being internal, and never pearly. Our description includesStomatella, Lam. The Stomatiæ are marine, and belong to the East Indies and New Holland. Fig. 335, S. Phymotis.STORILLUS. Montf. 1, 131. A genus of microscopic Foraminifera, included in the genus Rotalites in M. De Blainville's system.STRAPAROLLUS. Mont. A genus containing some species ofHelix, Auct. Generic characters not defined.STREPTAXIS. Gray.Fam.Colimacea, Lam.—Descr.Ovate, or oblong; when young, sub-hemispherical, deeply umbilicated, with rapidly enlarging whorls. At length the penultimate whorl is bent towards the right and dorsal side of the axis, and the umbilicus becomes depressed, and often nearly closed. The mouth is lunulate, the edge slightly thickened and reflected, and often with a single tooth on the outer side of the inner lip.—Obs.This genus of land shells is separated from Helix on account of the eccentricity of the penultimate whorl. S. contusa, fig. 269.STRIATED. (Stria, a groove.) Marked with fine grooves or lines.STRIGOCEPHALUS. Defr.Pentamerus, Sow.?Gypidia, Dalman.STROMBUS. Auct.Fam.Alatæ, Lam. Angiostomata, Bl.—Descr.Oblong, turrited, rather ventricose, solid; aperture generally lengthened, terminating posteriorly in a short canal, and anteriorly in an emargination or truncated canal; outer lip, when young, thin; when full grown, thickened and expanded, lobed at the spiral extremity, sinuated anteriorly near the caudal canal.—Obs.This well known genus includes some species of immense size, commonly called conch shells. Most of the recent species are brought from the Indian Ocean. Very few fossil species are known. The young shells have very much the appearance of cones, the outer lips being thin. There are also several species which do not, even when full grown, thicken their outer lips very considerably. The genus Strombus is distinguished from Rostellaria, by the notch in the outer lip, which in the latter genus is close to the canal. Fig. 406, S. pugilis.STROPHOMENA. Rafinesque.Orthis, Dalman.STROPHOSTOMA. Deshayes. A fossil shell, of the family of Colimacea, Lam. in some degree resembling Anostoma, having the aperture turned upwards towards the spire, it is, however, umbilicated, and is said to have an operculum resembling that of Cyclostoma. It is the Ferussina of Grateloup. Fig. 534, 5, 6.STRUTHIOLARIA. Auct. (Struthio, an Ostrich.)Fam.Canalifera, Lam.—Descr.Oblong, turrited, thick; spire turrited, composed of several angulated whorls; aperture oval, sub-quadrate, oblique; outer lip thickened, reflected, advancing in the centre, receding towards the extremities; inner lip thickened, expanded over the columella and part of the body whorl.—Obs.This singular genus, consisting of three or four recent species, is named "Pied D'Autruche" by the French, on account of some resemblance in the outer lip to the foot of the Ostrich. From New Zealand. Fig. 391, S. straminea.STYLIFER. Brod. (Stylus, a style;fero, to bear.)—Descr.Thin, pellucid, turbinated; apex a little out of the perpendicular; aperture wide anteriorly, gradually narrowing towards the spiral extremity, where it terminates acutely.—Obs.This is a genus of small, transparent shells, found burrowing in the rays of Starfish. There are but two or three species at present known, one of which is elongated like Terebra, the other nearly globular. Fig. 12, S. astericola. West Indies, Gallapagos, and Britain.STYLINA. Flem.Stylifer, Brod.SUB. (under.) Used as a prefix and signifying nearly. Thus a bivalve-shell, the valves of which are nearly alike, would be described assub-equivalve.SUB-APLYSIACEA. Bl. The first family of the order Monopleurobranchiata, Bl. containing several genera of Mollusca without shells, and the genus Pleurobranchus.SUB-BIVALVES. A term of distinction applied by De Blainville, to those spiral univalves which have an operculum; these, as they constitute two distinct pieces, he considers as forming a medium between univalves and bivalves.SUB-MYTILACEA. Bl. The sixth family of the order Lamellibranchiata, Bl. the shells belonging to which are described as free, rather pearly, regular, equivalve; hinge dorsal, laminated; ligament external; two muscular impressions; palleal impression not sinuated. This family, with the exception of the last genus, agrees with the family Nayades of Lamarck, and contains the genera Anodon, Unio, and Cardita.SUB-OSTRACEA. Bl. The second family of Lamellibranchiata, Bl. the shells of which are described as of a compact texture, sub-symmetrical; with the hinge rather complex; one single, sub-central, muscular impression, without any traces of palleal impression. This family corresponds with the Pectenides of Lamarck, and part of the genus Ostrea in the system of Linnæus. It contains the genera Spondylus, Plicatula, Hinnites, Pecten, Pedum, Lima.SUB-SPIRAL. Not sufficiently spiral to form a complete volution.SUBULA. Bl. (An awl.) A generic name under which M. De Blainville includesTerebramaculata, Auct. f. 428, together with nearly all the species of Terebra, enumerated by Lamarck and other authors; only leaving in the latter genus those species, which being more bulbous, or ventricose, nearly resemble Buccinum in general form. These last mentioned species, such as Terebra buccinoidea, (fig. 247) have been formed into a new genus by Mr. Gray, under the name Bullia. If both these genera were adopted, the genus Terebra would be extinct.SUBULATE. (Subula, an awl.) A term applied to shells which are long and pointed as in Terebra. Fig. 427, 428.SUCCINEA. Drap. (Succinum, amber.)Fam.Colimacea, Lam. Limacinea, Bl.Sub-genus, Cochlohydra, Fer.—Descr.Ovate, rather elongated; aperture large, entire, longitudinal; spire short; outer lip thin, continuous with the thin, sharp-edged columella; inner lip spread over a part of the body-whorl.—Obs.The shells belonging to this genus of partly amphibious mollusca, are distinguished from Limnæa by not having a fold on the columella The S. amphibia is of a bright amber colour. Fig. 265, 266. Temperate and tropical climates.SULCATED. (Sulcatus, lat.) Having grooves or furrows.SULCI. Grooves or furrows.SUTURE. (Sutura, lat.) A seam, stitch, joining together. Applied particularly to the line which marks the joining of the whorls of the spire. The suture is distinguished assimple, as in most cases; ordouble, when accompanied by a parallel groove close to it;marginated, when produced into a ledge by the matter which fills up and covers it;obsolete, when it is filled up so as not to be visible, as in the case of Ancillaria.SYLVICOLA. Humph.Cyclostoma, Lam.SYMMETRICAL, (συν,syn, similar;μετρον,metron, proportion.) Both sides alike. Although the term is used thus as one of distinction, it is to be observed that no shells are strictly and perfectly symmetrical; even in the Nautilus, the apex verges in a slight degree towards one side of the shell. Two kinds of univalve are symmetrical, or nearly so; 1st. Those which are symmetrically convolute, as the Nautilacea and the Ammonacea, which are spiral; 2nd. Those which are not spiral, but simply conical, as the patelliform shells. Bivalves belonging to the Brachiopoda are also symmetrical.Ex.Patella, fig. 229. Ammonites, fig. 478.SYMPHYNOTA. Lea. A genus of Nayades, in which Mr. Lea proposed to include species of the genusUnio, the valves of which are connate, or united at the dorsal margin. We believe that this distinction, as a genus, has been abandoned by its author. The fact is, that all the Uniones are Symphynotæ when in a young state. In Unio Alatus, (fig. 147) and Dipsas plicatus, (fig. 142) it will be observed that the valves have not separated at the dorsal edge, but are broken lower down.TAPADA. (Gray. Turton. p. 127.) A division of the genusHelix, containingHelixaperta, Auct. or the Tapada snail.TAPES. Schum.Pullastra.Sow.?TECTUS. Montf. A genus composed of species of the genus Trochus, having elevated, conical spires, and columella notched or truncated by a spiral fold. Fig. 359. Trochus maculatus, presents an example.TELEBOIS. Montf. A genus of microscopic Foraminifera.TELESCOPIUM. Montf.CerithiumTelescopium, Auct. fig. 378.TELLINA. Linn.Fam.Nymphacea, Lam. Conchacea, Bl.—Descr.Sub-equivalve, inequilateral, compressed, rounded anteriorly, slightly beaked or angulated posteriorly, the posterior ventral margin having a flexuosity; hinge with two cardinal and generally two lateral teeth in each valve; muscular impressions, two in each valve, remote; palleal impression with a large sinus.—Obs.The fold or bending in the posterior margin distinguishes this genus from others which it nearly resembles. It is composed of some bivalves of great beauty and variety, which are found in nearly all climates. Fig. 105, T. radiata, 106, T. lingua-felis.TELLINIDES. Lam.Fam.Nymphacea, Lam.—Descr.Sub-equivalve, inequilateral, transverse, compressed, rounded anteriorly, slightly beaked or angulated posteriorly; hinge with two cardinal teeth in each valve, and one lateral tooth in one valve, very near the cardinal teeth. Muscular impressions two, distant, palleal impression with a large sinus.Obs.This genus is distinguished from Tellina in having but one lateral tooth near the cardinal teeth. Fig. 107, T. rosea. Tropical.TENUIPEDES. (Tenuis, slender;pedes, feet.) The second section of the order Conchifera Dimyaria, divided into the families Mactracea, Corbulacea, Lithophagidæ, Nymphacea.TERACLITA. Schum.Conia, Auct.TEREBELLUM. Lam. (Terebra, an augur?)Fam.Convolutæ, Lam. Angyostomata, Bl.—Descr.Smooth, slender, oblong, sub-cylindrical; spire obtuse, short, sometimes hidden; (Seraphs, Montf.) aperture long, narrow posteriorly, wider anteriorly; outer lip slightly thickened, truncated, unconnected at the base with the columella; inner lip thin, smooth, nearly straight, spread over a portion of the body-whorl, continued in a ridge above the sutures of the spire.—Obs.Montfort has separated the fossil species with hidden spires, under the name Seraphs. (T. convolutum, Lam.) Only one recent species is known, of which there are several varieties, one spotted, one marked in sub-spiral lines, another in patches. It is brought from the East Indies. Fig. 451, T. convolutum; 452, T. subulatum.TEREBRA. (An augur, a piercer.)Fam.Purpurifera, Lam. Entomostomata, Bl.—Descr.Subulate, elongated, pointed, turrited; spire long, consisting of numerous whorls; aperture small terminating in a short, reflected canal; outer lip thin; columella tortuous; operculum horny. The recent species are mostly tropical.—Obs.Nearly all the species enumerated by Lamarck and other authors are included by De Blainville in his genus Subula; those few species which that conchologist left in the present genus, being shorter and more ventricose than the others, approximate in shape to some of the Buccina, and are distinguished by Mr. Gray under the generic name Bullia. It seems strange, that De Blainville, being convinced of the necessity of separating the two groups, and consequently applying a new generic term to one of them, should have given that term to the larger number and the more typical species of the Lamarckian genus. Fig. 427, Bullia vittata. (Terebra.) Fig. 428, Terebra maculata. (Subula.)TEREBRALIA. Sw. A genus of "Cerithinæ," Sw. thus described: "Outer lip much dilated, generally uniting at its base to the inner lip; leaving a round perforation at the base of the pillar; channel truncate; operculum round: palustre. Mart. f. 1472." Sw. p. 315.TEREBRATING SHELLS. (Terebro, to pierce.) Shells which reside in holes pierced in rocks, wood, &c. by means of some corrosive secretion of the animal.Ex.Pholas, Teredo, &c.TEREBRATULA. Brug. (Terebrans, bored.)Fam.Brachiopoda, Lam.—Order.Palliobranchiata, Bl.—Descr.Inequivalve, equilateral, oval or sub-trigonal, ventricose or compressed, attached by a tendon passing through an opening in the dorsal, or upper and larger valve, the umbo of which advances beyond that of the other valve; hinge destitute of a ligament, with two teeth in the dorsal valve, locked into corresponding cavities in the ventral, or lower valve, and with two curious processes originating at the umbo of the lower valve, presenting, in some species, the appearance of fine winding tape, advancing towards the front of the valve, and again receding to the centre, where the ends unite; muscular impressions two, placed near the centre of each valve.—Obs.The Terebratulæ are included in the genus Anomia in the system of Linnæus. The recent species are not very numerous—they are found in all climates. The fossil species are more numerous than the recent ones, occurring in the secondary and tertiary formations. T. Psittacea, fig. 202.TEREDINA. (From Teredo.)Fam.Tubicolæ, Lam. Adesmacea, Bl.—Descr.Valves equal, inequilateral, with prominent umbones, as it were soldered to the outside of the rounded end of a shelly tube, of which they form a part; aperture of the tube partly divided; a flat accessary valve placed on the umbones.—Obs.This genus, which is only known in a fossil state, is distinguished from Teredo, by the valves being fixed on the tube, and the tube being closed at one extremity. Fig. 46, 47, T. personata.TEREDO. Auct. (A piercer.)Fam.Tubicolæ, Lam. Adesmacea, Bl.—Descr.Valves equal, inequilateral; presenting when closed, an orbicular figure, with a large angular opening in front, and a rounded opening at the back; placed at the anterior extremity of an irregular, flexuous, elongated tube, open at both ends; the anterior termination divided in a double aperture opened and closed at the will of the animal by two opercula.—Obs.This genus of Molluscous Animals, is remarkable for boring holes in wood, which are filled by their elongated tubes, and give it a honey-comb appearance. Fig. 48. T. Navalis. Fig. 49, a piece of bored wood.TERMINAL. When the umbones of a bivalve shell are placed at or near the extremity, as in Mytilus, fig. 158, Pinna, fig. 162, they are said to beterminal. The same term is also applied to the nucleus of an operculum, when it forms an extreme point, or is close to one of the edges.TESSELLATED. (Wrought in chequer-work). A term applied to the colouring of shells, when arranged in regular defined patches like a tessellated pavement.TESTACELLA. (Testa, a shell.)Fam.Limacinea, Lam. and Bl.—Descr.Haliotoid, compressed; aperture wide, oblique; columella flat, oblique; spire short, flat, consisting of less than two whorls.—Obs.This shell which is extremely small compared with the animal, is placed upon its back, near the posterior extremity. The animal is found in some of our gardens, and very much resembles the common garden slug. Fig. 261, T. Haliotoidea.TESTACEOUS. (Testa, a shell.) Shelly. Testaceous Mollusca, are soft animals having shells. A testaceous operculum is one composed of shelly matter.TETRACERA. Bl. The first family of the order Polybranchiata, Bl. containing no genera of testaceous mollusca.TEXTILIA. Sw. A sub-genus of Conus, consisting of Conus bullatus, &c. Sw. Malac. p. 312.TEXTULARIA. Defr. A genus of microscopic Foraminifera.THALAMUS. Montf. A genus described as resembling Conilites, but curved and granulated.THALLEPUS. Sw. A genus of "Aplysianiæ," Sw. thus described: "Body more slender and fusiform;" (than Aplysia,) "the lobes of the mantle short, and incapable of being used for swimming; tentacula two, large, ear shaped; eyes not visible. T. ornatus,Sw.Sp. Nov." Sw. p. 359.THALLICERA. Sw. A generic name under which Swainson distinguishesAmpullariaAvellana, Auct.THECIDIUM. (Thecas, a box.)Fam.Brachiopoda, Lam.Order, Palliobranchiata, Bl.—Descr.Lower valve concave, sub-trigonal, with the umbo produced into a triangular, slightly incurved beak, and with two short, pointed processes advancing from beneath the umbones; upper valve flat, rounded square, with a short, blunt appendage, formed to fit between the tooth-like process of the other valve; its inner surface ornamented with symmetrically curved ridges.THECOSOMATA. Bl. The first family of the order Aporobranchiata, Bl. containing the genera Hyalæa, Cleodora, Cymbulia, Pyrgo.THELICONUS. Sw. A sub-genus of Conus. Lardn. Cyclop. Malac. p. 312.THELIDOMUS. Sw. A generic name under which Swainson has described a division of the genus Helix, and which he has also used to designate a genus in the family of "Rotellinæ," founded upon an aggregate of loose particles collected and agglutinated in a spiral form by the larva of an insect. Sw. Malac. p. 330 and 353.THEMEON. Montf. A genus of microscopic Foraminifera.THEODOXUS. Montf. A division of the genus Nerita. Fig. 324, N. virginea.THETIS. Sow. (A sea nymph.) A genus of fossil shells, described as resembling Mactra, but not having the internal ligament, and having several small, acuminated, cardinal teeth, but no lateral teeth. It resembles Tellina in some degree, but has not the posterior fold.THIARELLA. Sw. A sub-genus of Mitra, Lardn. Cyclop. Malac. p. 319.THRACIA. Leach.Fam.Lithophagidæ, Lam. Pyloridea, Bl. A genus described as intermediate between Anatina, and Mya, and in some degree resembling Corbula. T. corbuloides, fig. 93.THUNDER-STONES. One of the vulgar appellations which have been applied to shells of the genus Belemnites.THIATYRA. Leach. A genus composed ofAmphidesmaflexuosa, Lam. and similar species, belonging more properly to the genusLucina.TIARA. Sw. A genus of "Mitranæ," Sw. thus described: "Aperture narrow, linear, or of equal breadth throughout; outer lip and base of the body whorl contracted, the former generally striated; an internal canal at the upper part of the aperture; shell (typically) turrited, and equally fusiform; representing theMuricidæand Cymbiola." Sw. Malac. p. 319. The principal difference between Tiara and Mitra appears to be that in the latter, the aperture is more linear and contracted in the centre. Mitra Episcopalis is an example.TINOPORUS. Montf. A genus of microscopic Foraminifera.TIRANITES. Montf. A division of the genus Baculites.TOMELLA. Sw. A genus of "Pleurotominæ," Sw. thus described: "Fusiform, smooth; the spire of very few whorls, and not longer than the channel; inner lip with a thick callosity at the top; the slit short and wide; lineata, En. Méth. 440, f. 2, clavicularis, Ib. f. 4. filosa. En. Méth. 440, f. 6. lineolata. Ib. f. 11." Sw. p. 314.TOMOGERUS. Montf.Anastoma, Auct. Fig. 471.TONICHIA. Gray. Syn. B. M. p. 126. A genus composed of those species of Chiton which have the margin smooth.TORNATELLA. Auct.Fam.Plicacea, Lam.—Descr.Oval, spirally grooved; spire short, rather obtuse, consisting of few whorls; aperture long, narrow, rounded anteriorly; outer lip simple; inner lip thin, slightly spread, columella spiral, incrassated, confluent with the outer lip. The recent species are few. Several fossil species occur in London Clay, Inferior Oolite and Calcaire-grossièr. Monoptygma, Lea, resembles this genus, but has a fold on the inner lip. Fig. 343, T. solidula.TORTUOUS. (Tortuosus) Twisted. This adjective is sometimes applied as a specific name; as Arca tortuosa.TRACHELIPODA. Lam. (τραχηλος,trachelos, a neck;ποδα,poda, foot.) The third order of the class Mollusca, in the system of Lamarck. The trachelipodous mollusca are described as having the posterior part of the body spirally twisted and separated from the foot; always enveloped in a shell. The foot is free, flat, attached to the base of the neck. Shell spiral, and enclosing the animal when at rest. This order contains the families, Colimacea, Lymnacea, Melaniana, Peristomiana, Neritacea, Janthinea, Macrostomata, Scalariana, Plicacea, Canalifera, Alata, Purpurifera, Columellaria, Convolutæ. The genera belonging to these families, are represented in the plates, fig. 264, to 462.TRANSVERSE. (Crosswise.) A shell is said to be transverse, when its width is greater than its length, that is, when it is longer from one side to the other than from the umbones to the ventral margins. The term is applied by some authors to express the direction of the lines of growth in bivalve shells, and the spiral lines in spiral shells. SeeConcentric.TRAPEZIUM. Meg.Cypricardia, Lam.TRAPEZIFORM, orTRAPEZOID. (τραπεζιον,trapezion,trapezium;ειδος,eidos, form.) Having four unequal and unparallel sides.Ex.Cucullæa, fig. 133.TRIBULUS. Klein.Ricinula, Lam.TRICHOTROPIS. Brod. and Sow. (Τριχος,trichos, hair;τροπιςtropis, keel.)Fam.Purpurifera, Lam.—Descr.Turbinated, keeled, thin, umbilicated; aperture longer than the spire, entire; columella obliquely truncated; outer lip thin, sharp; epidermis horny, produced into long hairs at the angles of the shell; operculum horny, with the nucleus lateral.—Obs.Although the shells of this genus have something of the shape of Turbo, they are distinguished from that genus at once by the thinness of the shell. They are also known from Buccinum, by the absence of a canal. Only two or three species are known, which belong to the Northern and Arctic Oceans. T. bicarinata, fig. 429.TRIDACNA. Auct.Fam.Tridacnacea, Lam. Chamacea, Bl.—Descr.Equivalve, regular, inequilateral, radiately ribbed, adorned on the ribs with vaulted foliations, waved at the margins, with a large, anterior hiatus close to the umbones, for the passage of a large byssus, by which the animal fixes itself to marine substances; hinge with a partly external ligament; two laminar teeth in one valve, one in the other.—Obs.The beautiful shells composing this genus are of a delicate white colour, tinged with buff. One species, the T. gigas, attains a remarkable size, measuring from two to three feet across, and weighing five hundred pounds. Tridacna is distinguished from Hippopus by the large opening in the hinge. T. elongata, fig. 157.TRIDACNACEA. Lam. A family belonging to the first section of the order Conchifera Dimyaria, Lam. described as regular, equivalve, solid, and which are remarkable for the deeply sinuated or undulated ventral margin. This family contains the genera:

SOLENELLA. Sow. (Solen.)Fam.Arcacea, Lam.—Descr.Oval, equivalve, subequilateral, compressed, covered with a thin, shining, olive-green epidermis; hinge with three or four anterior, and numerous sharp posterior lateral teeth, arranged in a straight line; muscular impressions two, lateral; palleal impression with a large sinus; ligament external, prominent, elongated.—Obs.This genus partakes of the characters of the genus Nucula, and of the family Solenacea. A few specimens of the only species known (S. Norrisii, fig. 138.) were dredged by Mr. Cuming at Valparaiso.

SOLENIMYA. Lam. (Solen and Mya.)Fam.Mactracea, Lau. Pyloridea, Bl.—Descr.Equivalve, inequilateral, transversely oblong, rounded at the extremities with the umbones near the posterior side, covered with a shining brown epidermis extending beyond the edges of the shell; hinge without teeth; ligament partly internal, placed in the margin of an oblique, flattish, posterior rib; muscular impressions two, distant, lateral. From the Mediterranean, Australian, and Atlantic Oceans.—Obs.Solenimya differs from Solenocurtus and the true Solens, in having the posterior side of the shell the shortest; in the internal ligament; and in being destitute of teeth. It resembles Glycimeris, but is not incrassated. Fig. 68, Solenimya radiata.

SOLENOCURTUS. Bl. (Solenandcurtus, short.)Fam.Pyloridea, Bl. Solenacea, Lam.—Descr.Oval, elongated, equivalve, sub-equilateral, with the edges nearly straight and parallel, and the extremities rather truncated; umbones not very prominent, sub-central; hinge with or without two or three rudimentary cardinal teeth; ligament prominent, placed upon thick callosities; muscular impressions two, distant, rounded; palleal impression straight, with a deep sinus. East Indies—Obs.Distinguished from the true Solenes by the central position of the umbones and an internal bar reaching partly across the shell.

SOLETELLINA. Bl.Sanguinolariaradiata. S. Diphos, f. 99. S. livida of Sowerby, and similar species, are placed together in this genus.

SPATHA. Lea. A sub-genus ofIridinæ, consisting of I. rubens and I. nilotica, which have not distinctly crenulated margins. Spatha solenoides, of Lea, is the genus Mycetopus D'Orbigny. Fig. 151.

SPHÆNIA. Turt. A genus consisting of a small species resembling Saxicava, in general appearance, but having a spoon-shaped process on the hinge of one valve. S. Binghamii, Fig. 96.

SPHÆROIDINA. D'Orb. A genus of microscopic Foraminifera.

SPHÆRULACEA. Bl. The first family of Cellulacea consisting of the following genera of microscopic Foraminifera: Miliola, Melonia, Saracenaria, Textularia.

SPHÆRULACEA. Lam. The fourth family of Cephalopoda, Lam. described as multilocular, globular, sphærical, or oval, with the whorls enveloping each other; some of them have a particular internal cavity, and are composed of a series of elongated, straight and contiguous chambers which altogether form a covering for the internal cavity. This family contains the genera Miliola, Gyrogona and Melonia.

SPHÆRULITES. Lam. (Sphæra, a sphere.)Fam.Rudistes, Lam. and Bl.—Descr.Orbicular, inequivalve, irregularly foliated outside; lower valve cup-shaped, depressed; upper valve nearly flat, like an operculum.—Obs.These fossils are not regarded as shells by all conchologists. S. foliacea, Fig. 193.

SPHINCTERULUS. Montf.Lenticulina, Bl. A genus of microscopic Foraminifera.

SPINES. (Spina, a thorn.) Thin, pointed spikes.

SPINOSE. (Spinosus.) Having spines or elevated points, as Neritina spinosa. Fig. 325.

SPIRAL. (Spira, a spire.) Revolving outwards from a central apex or nucleus, like the spring of a watch. A shell or an operculum, may be spiral, without being produced into a pyramid. Bands of colour, striæ, grooves, &c. commencing from the nucleus and following the volutions of the shell, are described by the above word.

SPIRAMILLA. Bl. A genus of Serpulacea, differing from other Serpulæ principally in the characters of the animal.

SPIRATELLA. Bl.Limacinea, Lam. Fig. 224.

SPIRE. (Spira.) The cone or pyramid produced in a non-symmetrical univalve by its oblique revolution downwards from the apex or nucleus. The spire, in descriptions, includes all the volutions above the aperture. See Introduction.

SPIRIFER. Sow. (Spira, a spire;fero, to bear.)Order, Brachiopoda, Lam.—Descr.Transverse, equilateral; hinge linear, straight, widely extended on both sides of the umbones, which are separated by a flat area in the upper and larger valve; this area is divided in the centre by a triangular pit for the passage of the byssus; interior with two spirally convolute appendages.—Obs.This genus, which is only known in a fossil state, is distinguished from Terebratula externally, by the flat area in one valve, internally, by the singular spiral process from which the above name is derived. Fig. 214, 215. Most of the species belong to the mountain or carboniferous limestone.

SPIROGLYPHUS. Daud. A genus consisting of a species of SerpulaAuct.which makes a groove for itself in the surface of shells. Serpula spirorbis, var. Dillwyn. Fig. 8.

SPIROLINA. Lam. A genus of microscopic Foraminifera.

SPIROLOCULINA. D'Orb. A genus of microscopic Foraminifera.

SPIRORBIS. Lam. A genus composed of species ofSerpula, Auct. which are coiled round in a spiral disc like a snake at rest. S. nautiloides, fig. 5, is the common little white shell, found upon the shell of lobsters.

SPIRULA. (Spira, a winding compass.)Fam.Lituolata, Lam. Lituacea, Bl.—Descr.Convolute, smooth, symmetrical, discoid, with parallel unconnected whorls, divided into numerous chambers by transverse septa; siphon continuous.—Obs.This pretty little shell is partly internal, only a part of it being visible when on the animal. Fig. 471.

SPISULA. Gray. A genus composed ofMactrafragilis, and other similar species, which have the ligament sub-external, marginal, not separate from the cartilage; with the posterior lateral teeth double in one valve, and single in the other. M. fragilis, fig. 80, is the species figured for Spisula in Mr. Gray's paper on the Mactradæ, in the second series of Loudon's Magazine of Natural History. We have since learned, however, that it was figured there by mistake, not having been intended for a Spisula, but belonging more properly to the genus Mactra, as defined by Mr. Gray, whose description of Spisula, is as follows:—"Shell ovate, trigonal, sub-angular at each end. Hinge and lateral teeth as in Mactra, but hinge of left tooth small. Siphonal inflexion ovate." The principal difference between Spisula and Mactra is, that the ligament is not separated from the cartilage in the former.

SPONDYLUS. Auct. (A shell-fish, Ancients.)Fam.Pectenides, Lam. Sub-ostracea, Bl.—Descr.Inequivalve, sub-equilateral, irregularly foliaceous and spinose, auriculated, denticulated at the margins, attached by the lower and deeper valve; hinge rectilinear, with two prominent teeth in each valve, locking into corresponding cavities in the opposite valve; umbones separated by a broad, elongated, triangular disc in the lower valve; ligament contained in a groove, dividing the triangular area in the centre; muscular impressions one in each valve, sub-central, sub-orbicular. The Mediterranean, East and West Indies, and China, produce Spondyli most abundantly.—Obs.This genus is remarkable for the richness and beauty of the spines and foliations, which adorn the external surface of most of the species, the splendid colours by which many of them are varied, and the natural groupings formed by their attachment to each other. Fig. 177, and Frontispiece.

SPORULUS. Montf. A genus of microscopic Foraminifera.

SQUAMOSE. (Squama, a scale.) Scaly, covered with scales, as the pedicle of Pollicipes Mitellus, fig. 37*.

STENOPUS. Guild. (Στενος, narrow,πους, foot.) A genus nearly "allied to the Linnæan Helices, from all of which it differs in the curious contraction of the pedal disc, and the caudal tentaculum furnished with a gland beneath." The shell is described as heliciform, umbilicated, transparent, with the aperture transverse. The two species described are Stenopus cruentatus and lividus; they are both from the Caribbæan Islands, Guild. Zool. Journ. xii. p. 528, tab. 15, f. 1 to 5.

STOMATELLA. Lam. SeeStomatia.

STOMATIA. Auct. (στομα,stoma, mouth.)Fam.Macrostomata, Lam.—Descr.Sub-orbicular, oblong, auriform, variegated without, iridescent within; spire depressed; aperture entire, very wide, oblique; peritreme uninterrupted.Obs.This genus is known from Haliotis by being destitute of the series of holes; is distinguished from Sigaretus by the substance of the shell, the latter being internal, and never pearly. Our description includesStomatella, Lam. The Stomatiæ are marine, and belong to the East Indies and New Holland. Fig. 335, S. Phymotis.

STORILLUS. Montf. 1, 131. A genus of microscopic Foraminifera, included in the genus Rotalites in M. De Blainville's system.

STRAPAROLLUS. Mont. A genus containing some species ofHelix, Auct. Generic characters not defined.

STREPTAXIS. Gray.Fam.Colimacea, Lam.—Descr.Ovate, or oblong; when young, sub-hemispherical, deeply umbilicated, with rapidly enlarging whorls. At length the penultimate whorl is bent towards the right and dorsal side of the axis, and the umbilicus becomes depressed, and often nearly closed. The mouth is lunulate, the edge slightly thickened and reflected, and often with a single tooth on the outer side of the inner lip.—Obs.This genus of land shells is separated from Helix on account of the eccentricity of the penultimate whorl. S. contusa, fig. 269.

STRIATED. (Stria, a groove.) Marked with fine grooves or lines.

STRIGOCEPHALUS. Defr.Pentamerus, Sow.?Gypidia, Dalman.

STROMBUS. Auct.Fam.Alatæ, Lam. Angiostomata, Bl.—Descr.Oblong, turrited, rather ventricose, solid; aperture generally lengthened, terminating posteriorly in a short canal, and anteriorly in an emargination or truncated canal; outer lip, when young, thin; when full grown, thickened and expanded, lobed at the spiral extremity, sinuated anteriorly near the caudal canal.—Obs.This well known genus includes some species of immense size, commonly called conch shells. Most of the recent species are brought from the Indian Ocean. Very few fossil species are known. The young shells have very much the appearance of cones, the outer lips being thin. There are also several species which do not, even when full grown, thicken their outer lips very considerably. The genus Strombus is distinguished from Rostellaria, by the notch in the outer lip, which in the latter genus is close to the canal. Fig. 406, S. pugilis.

STROPHOMENA. Rafinesque.Orthis, Dalman.

STROPHOSTOMA. Deshayes. A fossil shell, of the family of Colimacea, Lam. in some degree resembling Anostoma, having the aperture turned upwards towards the spire, it is, however, umbilicated, and is said to have an operculum resembling that of Cyclostoma. It is the Ferussina of Grateloup. Fig. 534, 5, 6.

STRUTHIOLARIA. Auct. (Struthio, an Ostrich.)Fam.Canalifera, Lam.—Descr.Oblong, turrited, thick; spire turrited, composed of several angulated whorls; aperture oval, sub-quadrate, oblique; outer lip thickened, reflected, advancing in the centre, receding towards the extremities; inner lip thickened, expanded over the columella and part of the body whorl.—Obs.This singular genus, consisting of three or four recent species, is named "Pied D'Autruche" by the French, on account of some resemblance in the outer lip to the foot of the Ostrich. From New Zealand. Fig. 391, S. straminea.

STYLIFER. Brod. (Stylus, a style;fero, to bear.)—Descr.Thin, pellucid, turbinated; apex a little out of the perpendicular; aperture wide anteriorly, gradually narrowing towards the spiral extremity, where it terminates acutely.—Obs.This is a genus of small, transparent shells, found burrowing in the rays of Starfish. There are but two or three species at present known, one of which is elongated like Terebra, the other nearly globular. Fig. 12, S. astericola. West Indies, Gallapagos, and Britain.

STYLINA. Flem.Stylifer, Brod.

SUB. (under.) Used as a prefix and signifying nearly. Thus a bivalve-shell, the valves of which are nearly alike, would be described assub-equivalve.

SUB-APLYSIACEA. Bl. The first family of the order Monopleurobranchiata, Bl. containing several genera of Mollusca without shells, and the genus Pleurobranchus.

SUB-BIVALVES. A term of distinction applied by De Blainville, to those spiral univalves which have an operculum; these, as they constitute two distinct pieces, he considers as forming a medium between univalves and bivalves.

SUB-MYTILACEA. Bl. The sixth family of the order Lamellibranchiata, Bl. the shells belonging to which are described as free, rather pearly, regular, equivalve; hinge dorsal, laminated; ligament external; two muscular impressions; palleal impression not sinuated. This family, with the exception of the last genus, agrees with the family Nayades of Lamarck, and contains the genera Anodon, Unio, and Cardita.

SUB-OSTRACEA. Bl. The second family of Lamellibranchiata, Bl. the shells of which are described as of a compact texture, sub-symmetrical; with the hinge rather complex; one single, sub-central, muscular impression, without any traces of palleal impression. This family corresponds with the Pectenides of Lamarck, and part of the genus Ostrea in the system of Linnæus. It contains the genera Spondylus, Plicatula, Hinnites, Pecten, Pedum, Lima.

SUB-SPIRAL. Not sufficiently spiral to form a complete volution.

SUBULA. Bl. (An awl.) A generic name under which M. De Blainville includesTerebramaculata, Auct. f. 428, together with nearly all the species of Terebra, enumerated by Lamarck and other authors; only leaving in the latter genus those species, which being more bulbous, or ventricose, nearly resemble Buccinum in general form. These last mentioned species, such as Terebra buccinoidea, (fig. 247) have been formed into a new genus by Mr. Gray, under the name Bullia. If both these genera were adopted, the genus Terebra would be extinct.

SUBULATE. (Subula, an awl.) A term applied to shells which are long and pointed as in Terebra. Fig. 427, 428.

SUCCINEA. Drap. (Succinum, amber.)Fam.Colimacea, Lam. Limacinea, Bl.Sub-genus, Cochlohydra, Fer.—Descr.Ovate, rather elongated; aperture large, entire, longitudinal; spire short; outer lip thin, continuous with the thin, sharp-edged columella; inner lip spread over a part of the body-whorl.—Obs.The shells belonging to this genus of partly amphibious mollusca, are distinguished from Limnæa by not having a fold on the columella The S. amphibia is of a bright amber colour. Fig. 265, 266. Temperate and tropical climates.

SULCATED. (Sulcatus, lat.) Having grooves or furrows.

SULCI. Grooves or furrows.

SUTURE. (Sutura, lat.) A seam, stitch, joining together. Applied particularly to the line which marks the joining of the whorls of the spire. The suture is distinguished assimple, as in most cases; ordouble, when accompanied by a parallel groove close to it;marginated, when produced into a ledge by the matter which fills up and covers it;obsolete, when it is filled up so as not to be visible, as in the case of Ancillaria.

SYLVICOLA. Humph.Cyclostoma, Lam.

SYMMETRICAL, (συν,syn, similar;μετρον,metron, proportion.) Both sides alike. Although the term is used thus as one of distinction, it is to be observed that no shells are strictly and perfectly symmetrical; even in the Nautilus, the apex verges in a slight degree towards one side of the shell. Two kinds of univalve are symmetrical, or nearly so; 1st. Those which are symmetrically convolute, as the Nautilacea and the Ammonacea, which are spiral; 2nd. Those which are not spiral, but simply conical, as the patelliform shells. Bivalves belonging to the Brachiopoda are also symmetrical.Ex.Patella, fig. 229. Ammonites, fig. 478.

SYMPHYNOTA. Lea. A genus of Nayades, in which Mr. Lea proposed to include species of the genusUnio, the valves of which are connate, or united at the dorsal margin. We believe that this distinction, as a genus, has been abandoned by its author. The fact is, that all the Uniones are Symphynotæ when in a young state. In Unio Alatus, (fig. 147) and Dipsas plicatus, (fig. 142) it will be observed that the valves have not separated at the dorsal edge, but are broken lower down.

TAPADA. (Gray. Turton. p. 127.) A division of the genusHelix, containingHelixaperta, Auct. or the Tapada snail.

TAPES. Schum.Pullastra.Sow.?

TECTUS. Montf. A genus composed of species of the genus Trochus, having elevated, conical spires, and columella notched or truncated by a spiral fold. Fig. 359. Trochus maculatus, presents an example.

TELEBOIS. Montf. A genus of microscopic Foraminifera.

TELESCOPIUM. Montf.CerithiumTelescopium, Auct. fig. 378.

TELLINA. Linn.Fam.Nymphacea, Lam. Conchacea, Bl.—Descr.Sub-equivalve, inequilateral, compressed, rounded anteriorly, slightly beaked or angulated posteriorly, the posterior ventral margin having a flexuosity; hinge with two cardinal and generally two lateral teeth in each valve; muscular impressions, two in each valve, remote; palleal impression with a large sinus.—Obs.The fold or bending in the posterior margin distinguishes this genus from others which it nearly resembles. It is composed of some bivalves of great beauty and variety, which are found in nearly all climates. Fig. 105, T. radiata, 106, T. lingua-felis.

TELLINIDES. Lam.Fam.Nymphacea, Lam.—Descr.Sub-equivalve, inequilateral, transverse, compressed, rounded anteriorly, slightly beaked or angulated posteriorly; hinge with two cardinal teeth in each valve, and one lateral tooth in one valve, very near the cardinal teeth. Muscular impressions two, distant, palleal impression with a large sinus.Obs.This genus is distinguished from Tellina in having but one lateral tooth near the cardinal teeth. Fig. 107, T. rosea. Tropical.

TENUIPEDES. (Tenuis, slender;pedes, feet.) The second section of the order Conchifera Dimyaria, divided into the families Mactracea, Corbulacea, Lithophagidæ, Nymphacea.

TERACLITA. Schum.Conia, Auct.

TEREBELLUM. Lam. (Terebra, an augur?)Fam.Convolutæ, Lam. Angyostomata, Bl.—Descr.Smooth, slender, oblong, sub-cylindrical; spire obtuse, short, sometimes hidden; (Seraphs, Montf.) aperture long, narrow posteriorly, wider anteriorly; outer lip slightly thickened, truncated, unconnected at the base with the columella; inner lip thin, smooth, nearly straight, spread over a portion of the body-whorl, continued in a ridge above the sutures of the spire.—Obs.Montfort has separated the fossil species with hidden spires, under the name Seraphs. (T. convolutum, Lam.) Only one recent species is known, of which there are several varieties, one spotted, one marked in sub-spiral lines, another in patches. It is brought from the East Indies. Fig. 451, T. convolutum; 452, T. subulatum.

TEREBRA. (An augur, a piercer.)Fam.Purpurifera, Lam. Entomostomata, Bl.—Descr.Subulate, elongated, pointed, turrited; spire long, consisting of numerous whorls; aperture small terminating in a short, reflected canal; outer lip thin; columella tortuous; operculum horny. The recent species are mostly tropical.—Obs.Nearly all the species enumerated by Lamarck and other authors are included by De Blainville in his genus Subula; those few species which that conchologist left in the present genus, being shorter and more ventricose than the others, approximate in shape to some of the Buccina, and are distinguished by Mr. Gray under the generic name Bullia. It seems strange, that De Blainville, being convinced of the necessity of separating the two groups, and consequently applying a new generic term to one of them, should have given that term to the larger number and the more typical species of the Lamarckian genus. Fig. 427, Bullia vittata. (Terebra.) Fig. 428, Terebra maculata. (Subula.)

TEREBRALIA. Sw. A genus of "Cerithinæ," Sw. thus described: "Outer lip much dilated, generally uniting at its base to the inner lip; leaving a round perforation at the base of the pillar; channel truncate; operculum round: palustre. Mart. f. 1472." Sw. p. 315.

TEREBRATING SHELLS. (Terebro, to pierce.) Shells which reside in holes pierced in rocks, wood, &c. by means of some corrosive secretion of the animal.Ex.Pholas, Teredo, &c.

TEREBRATULA. Brug. (Terebrans, bored.)Fam.Brachiopoda, Lam.—Order.Palliobranchiata, Bl.—Descr.Inequivalve, equilateral, oval or sub-trigonal, ventricose or compressed, attached by a tendon passing through an opening in the dorsal, or upper and larger valve, the umbo of which advances beyond that of the other valve; hinge destitute of a ligament, with two teeth in the dorsal valve, locked into corresponding cavities in the ventral, or lower valve, and with two curious processes originating at the umbo of the lower valve, presenting, in some species, the appearance of fine winding tape, advancing towards the front of the valve, and again receding to the centre, where the ends unite; muscular impressions two, placed near the centre of each valve.—Obs.The Terebratulæ are included in the genus Anomia in the system of Linnæus. The recent species are not very numerous—they are found in all climates. The fossil species are more numerous than the recent ones, occurring in the secondary and tertiary formations. T. Psittacea, fig. 202.

TEREDINA. (From Teredo.)Fam.Tubicolæ, Lam. Adesmacea, Bl.—Descr.Valves equal, inequilateral, with prominent umbones, as it were soldered to the outside of the rounded end of a shelly tube, of which they form a part; aperture of the tube partly divided; a flat accessary valve placed on the umbones.—Obs.This genus, which is only known in a fossil state, is distinguished from Teredo, by the valves being fixed on the tube, and the tube being closed at one extremity. Fig. 46, 47, T. personata.

TEREDO. Auct. (A piercer.)Fam.Tubicolæ, Lam. Adesmacea, Bl.—Descr.Valves equal, inequilateral; presenting when closed, an orbicular figure, with a large angular opening in front, and a rounded opening at the back; placed at the anterior extremity of an irregular, flexuous, elongated tube, open at both ends; the anterior termination divided in a double aperture opened and closed at the will of the animal by two opercula.—Obs.This genus of Molluscous Animals, is remarkable for boring holes in wood, which are filled by their elongated tubes, and give it a honey-comb appearance. Fig. 48. T. Navalis. Fig. 49, a piece of bored wood.

TERMINAL. When the umbones of a bivalve shell are placed at or near the extremity, as in Mytilus, fig. 158, Pinna, fig. 162, they are said to beterminal. The same term is also applied to the nucleus of an operculum, when it forms an extreme point, or is close to one of the edges.

TESSELLATED. (Wrought in chequer-work). A term applied to the colouring of shells, when arranged in regular defined patches like a tessellated pavement.

TESTACELLA. (Testa, a shell.)Fam.Limacinea, Lam. and Bl.—Descr.Haliotoid, compressed; aperture wide, oblique; columella flat, oblique; spire short, flat, consisting of less than two whorls.—Obs.This shell which is extremely small compared with the animal, is placed upon its back, near the posterior extremity. The animal is found in some of our gardens, and very much resembles the common garden slug. Fig. 261, T. Haliotoidea.

TESTACEOUS. (Testa, a shell.) Shelly. Testaceous Mollusca, are soft animals having shells. A testaceous operculum is one composed of shelly matter.

TETRACERA. Bl. The first family of the order Polybranchiata, Bl. containing no genera of testaceous mollusca.

TEXTILIA. Sw. A sub-genus of Conus, consisting of Conus bullatus, &c. Sw. Malac. p. 312.

TEXTULARIA. Defr. A genus of microscopic Foraminifera.

THALAMUS. Montf. A genus described as resembling Conilites, but curved and granulated.

THALLEPUS. Sw. A genus of "Aplysianiæ," Sw. thus described: "Body more slender and fusiform;" (than Aplysia,) "the lobes of the mantle short, and incapable of being used for swimming; tentacula two, large, ear shaped; eyes not visible. T. ornatus,Sw.Sp. Nov." Sw. p. 359.

THALLICERA. Sw. A generic name under which Swainson distinguishesAmpullariaAvellana, Auct.

THECIDIUM. (Thecas, a box.)Fam.Brachiopoda, Lam.Order, Palliobranchiata, Bl.—Descr.Lower valve concave, sub-trigonal, with the umbo produced into a triangular, slightly incurved beak, and with two short, pointed processes advancing from beneath the umbones; upper valve flat, rounded square, with a short, blunt appendage, formed to fit between the tooth-like process of the other valve; its inner surface ornamented with symmetrically curved ridges.

THECOSOMATA. Bl. The first family of the order Aporobranchiata, Bl. containing the genera Hyalæa, Cleodora, Cymbulia, Pyrgo.

THELICONUS. Sw. A sub-genus of Conus. Lardn. Cyclop. Malac. p. 312.

THELIDOMUS. Sw. A generic name under which Swainson has described a division of the genus Helix, and which he has also used to designate a genus in the family of "Rotellinæ," founded upon an aggregate of loose particles collected and agglutinated in a spiral form by the larva of an insect. Sw. Malac. p. 330 and 353.

THEMEON. Montf. A genus of microscopic Foraminifera.

THEODOXUS. Montf. A division of the genus Nerita. Fig. 324, N. virginea.

THETIS. Sow. (A sea nymph.) A genus of fossil shells, described as resembling Mactra, but not having the internal ligament, and having several small, acuminated, cardinal teeth, but no lateral teeth. It resembles Tellina in some degree, but has not the posterior fold.

THIARELLA. Sw. A sub-genus of Mitra, Lardn. Cyclop. Malac. p. 319.

THRACIA. Leach.Fam.Lithophagidæ, Lam. Pyloridea, Bl. A genus described as intermediate between Anatina, and Mya, and in some degree resembling Corbula. T. corbuloides, fig. 93.

THUNDER-STONES. One of the vulgar appellations which have been applied to shells of the genus Belemnites.

THIATYRA. Leach. A genus composed ofAmphidesmaflexuosa, Lam. and similar species, belonging more properly to the genusLucina.

TIARA. Sw. A genus of "Mitranæ," Sw. thus described: "Aperture narrow, linear, or of equal breadth throughout; outer lip and base of the body whorl contracted, the former generally striated; an internal canal at the upper part of the aperture; shell (typically) turrited, and equally fusiform; representing theMuricidæand Cymbiola." Sw. Malac. p. 319. The principal difference between Tiara and Mitra appears to be that in the latter, the aperture is more linear and contracted in the centre. Mitra Episcopalis is an example.

TINOPORUS. Montf. A genus of microscopic Foraminifera.

TIRANITES. Montf. A division of the genus Baculites.

TOMELLA. Sw. A genus of "Pleurotominæ," Sw. thus described: "Fusiform, smooth; the spire of very few whorls, and not longer than the channel; inner lip with a thick callosity at the top; the slit short and wide; lineata, En. Méth. 440, f. 2, clavicularis, Ib. f. 4. filosa. En. Méth. 440, f. 6. lineolata. Ib. f. 11." Sw. p. 314.

TOMOGERUS. Montf.Anastoma, Auct. Fig. 471.

TONICHIA. Gray. Syn. B. M. p. 126. A genus composed of those species of Chiton which have the margin smooth.

TORNATELLA. Auct.Fam.Plicacea, Lam.—Descr.Oval, spirally grooved; spire short, rather obtuse, consisting of few whorls; aperture long, narrow, rounded anteriorly; outer lip simple; inner lip thin, slightly spread, columella spiral, incrassated, confluent with the outer lip. The recent species are few. Several fossil species occur in London Clay, Inferior Oolite and Calcaire-grossièr. Monoptygma, Lea, resembles this genus, but has a fold on the inner lip. Fig. 343, T. solidula.

TORTUOUS. (Tortuosus) Twisted. This adjective is sometimes applied as a specific name; as Arca tortuosa.

TRACHELIPODA. Lam. (τραχηλος,trachelos, a neck;ποδα,poda, foot.) The third order of the class Mollusca, in the system of Lamarck. The trachelipodous mollusca are described as having the posterior part of the body spirally twisted and separated from the foot; always enveloped in a shell. The foot is free, flat, attached to the base of the neck. Shell spiral, and enclosing the animal when at rest. This order contains the families, Colimacea, Lymnacea, Melaniana, Peristomiana, Neritacea, Janthinea, Macrostomata, Scalariana, Plicacea, Canalifera, Alata, Purpurifera, Columellaria, Convolutæ. The genera belonging to these families, are represented in the plates, fig. 264, to 462.

TRANSVERSE. (Crosswise.) A shell is said to be transverse, when its width is greater than its length, that is, when it is longer from one side to the other than from the umbones to the ventral margins. The term is applied by some authors to express the direction of the lines of growth in bivalve shells, and the spiral lines in spiral shells. SeeConcentric.

TRAPEZIUM. Meg.Cypricardia, Lam.

TRAPEZIFORM, or

TRAPEZOID. (τραπεζιον,trapezion,trapezium;ειδος,eidos, form.) Having four unequal and unparallel sides.Ex.Cucullæa, fig. 133.

TRIBULUS. Klein.Ricinula, Lam.

TRICHOTROPIS. Brod. and Sow. (Τριχος,trichos, hair;τροπιςtropis, keel.)Fam.Purpurifera, Lam.—Descr.Turbinated, keeled, thin, umbilicated; aperture longer than the spire, entire; columella obliquely truncated; outer lip thin, sharp; epidermis horny, produced into long hairs at the angles of the shell; operculum horny, with the nucleus lateral.—Obs.Although the shells of this genus have something of the shape of Turbo, they are distinguished from that genus at once by the thinness of the shell. They are also known from Buccinum, by the absence of a canal. Only two or three species are known, which belong to the Northern and Arctic Oceans. T. bicarinata, fig. 429.

TRIDACNA. Auct.Fam.Tridacnacea, Lam. Chamacea, Bl.—Descr.Equivalve, regular, inequilateral, radiately ribbed, adorned on the ribs with vaulted foliations, waved at the margins, with a large, anterior hiatus close to the umbones, for the passage of a large byssus, by which the animal fixes itself to marine substances; hinge with a partly external ligament; two laminar teeth in one valve, one in the other.—Obs.The beautiful shells composing this genus are of a delicate white colour, tinged with buff. One species, the T. gigas, attains a remarkable size, measuring from two to three feet across, and weighing five hundred pounds. Tridacna is distinguished from Hippopus by the large opening in the hinge. T. elongata, fig. 157.

TRIDACNACEA. Lam. A family belonging to the first section of the order Conchifera Dimyaria, Lam. described as regular, equivalve, solid, and which are remarkable for the deeply sinuated or undulated ventral margin. This family contains the genera:

1.Hippopus. Valves closed at or near the hinge. Fig. 156.2.Tridacna. An hiatus near the hinge. Fig. 157.

1.Hippopus. Valves closed at or near the hinge. Fig. 156.

2.Tridacna. An hiatus near the hinge. Fig. 157.

TRIDENTATE. (Tridentatus.) Having three teeth, or salient points.Ex.Hyalæa tridentata, fig. 226.TRIGONA. Schum.? Triangular species ofCytherea, such as C. lævigata, Triplas corbicula, ventricosa, bicolor, &c. Fig. 117b.TRIGONACEA. Lam. A family belonging to the order Conchifera Dimyaria, containing the genera Trigonia and Castalia, the latter of which ought to be removed to the Nayades. Fig. 139, 140.TRIGONAL. Triangular, having three sides.TRIGONELLA. Humph.Mactra, Auct.TRIGONIA. Brug. (τριγωνον,trigonon, triangular.)Fam.Trigonata, Lam. Camacea, Bl.—Descr.Equivalve, inequilateral, transverse, sub-trigonal, costated and granulated without, pearly and iridescent within, denticulated on the inner margin, rounded anteriorly, truncated posteriorly; hinge with four oblong, compressed, diverging teeth in one valve, receiving between their grooved sides, two similar teeth in the other; ligament external, thick; muscular impressions two in each valve.—Obs.Only one recent species of this marine genus is known, the T. pectinata, which comes from New Holland; and was formerly so rare, that a much worn odd valve has been sold for a considerable sum. It is of a brilliant pearly texture within, tinged with purple or golden brown. Fossil species occur in Lias, upper and lower Oolite, and Green-sand. T. Pectinata, fig. 139.TRIGONOSEMUS. König. A genus composed of species ofTerebratula, Auct. which have one valve produced into a beak, perforated, or as it were truncated at the apex. T. lyra, fig. 208, differing from Terebratula lyra, Lam.TRIGONOSTOMA. A sub-genus of Helix, with a trigonal aperture. Gray's Turton, p. 139.TRIGONOTRETA. König. A genus composed of species of Terebratula, Auct. which have the hinge of the larger valve produced into a triangular disc, divided by a triangular foramen in the centre. Spirifer, Sowerby, belongs to this genus. Fig. 214, 215.TRILOBATE. (Τρειςthree;λοβος, division, lobe.) Divided into three lobes or principal parts. Ex. Malleus, Fig. 165.TRILOCULINA. D'Orbigny. A genus of microscopic Foraminifera.TRIPARTITE. (Tripartitus) composed of or divided into three separate parts.TRIPHORA, or TRISTOMA. Deshayes. A genus composed of small reversed species ofCerithium, Auct. which have the anterior canal closed at the anterior of the aperture, but opened at the extremity, and a small tubular opening on the upper part of the whorls, making three openings on the body whorl. This genus stands in the same relation to Cerithium as the Typhis to Murex. Fig. 375 in the old plates, and fig. in the new plates.TRIPLEX. Humph.Murex, Linn.TRIPLODON. Spix.Hyria, Auct.TRIPTERA. Quoy et Gaimard,Cuviera, Fer. Described in the Voyage de la Coquille, and represented as a molluscous animal destitute of a shell.TRIQUETRA. Bl. Triangular species ofVenusAuct.TRISIS. Oken.Arcatortuosa, Auct.TRISTOMA. Described asTriphora.TRITON. Auct.Fam.Siphonostomata, Bl. Canalifera, Lam.—Descr.Oblong or oval, thick, ribbed or tuberculated, with discontinuous varices placed at irregular distances; spire prominent, mammillated; aperture round or oval, terminating anteriorly in a generally long, slightly raised canal; columellar lip granulated or denticulated; outer lip thickened, reflected, generally denticulated within; epidermis rough; operculum horny.—Obs.However nearly allied the Tritons may appear to be to the Murices and Ranellæ there are still to be traced in the shells of each of those genera, several constant and well marked distinctions, by which they maybe at once recognized. In the Ranellæ, the varices run in two rows along the spire; in the Murices, they form three or more rows; but in the Tritons, they do not follow each other,i.e.they do not occur in the same part of each volution. The large species of Triton, are sometimes used as trumpets. The Tritons are brought from the Mediterranean, Ceylon, the East and West Indies, and South Seas. Fig. 398 to 401.TRITONIDEA. Sw. A genus of "Buccininæ," Sw. thus described: "Shell bucciniform, but the basal half is narrowed, and the middle more or less ventricose; spire and aperture equal. Pillar at the base with two or three obtuse and very transverse plaits, not well defined; outer lip internally crenated and with a superior siphon; inner lip wanting, or rudimentary." This genus is the same as the one first distinguished by Mr. Gray under the name of Pollia. We do not regret the discovery made by Mr. Swainson of that name being previously occupied for a genus of Lepidopterous Insects. Fig. 415, represents Tritonidea articularis. (Pollia, Gray.)TRIVIA. Gray. A genus composed of those small species ofCypræa, Auct. which are characterized by small ridges on the dorsal surface, and have the anterior of the columella internally concave and ribbed. C. Pediculus. Auct. fig. 449, 450.TROCHATELLA. Sw. A sub-genus of Helicinæ, consisting of those species which are acute and trochiform.TROCHIA. Sw. A genus of the family Buccininæ, thus described: "shape intermediate between Purpura and Buccinum; whorls separated by a deep groove; inner lip when young, depressed, when adult, thickened, convex and striated; basal canal very small. T. sulcatus. E. M. 422. f. 4." Sw. Malac. p. 300.TROCHIDON. Sw. A sub-genus of "Trochinæ," Sw. Lardn. Cyclop. Malac. p. 351.TROCHILÆA. Sw.?Pileolus, Auct.TROCHURUS. Humph.Monodonta. Lam.TROCHUS. Auct. (A top.)Fam.Turbinacea, Lam. Goniostomata, Bl.—Descr.Turbinated, thick, striated, tuberculated or smooth; spire elevated, conical, consisting of numerous whorls; under surface discoid; aperture more or less depressed in an oblique direction, generally angular; columella arcuated, more or less prominent at its union with the outer lip, contiguous to the axis of the shell; operculum horny, orbicular, with numerous whorls.—Obs.Lamarck distinguished this genus from Turbo by the general form, which is more conical, and the aperture, which is angulated, while that of Turbo is rounded. Monodonta or Odontis is only separated on account of the notch at the termination of the columella. But these characters glide so imperceptibly from one genus to the other, that there is no line of demarcation to be found but in the operculum. Accordingly, Sowerby (in Gen. of Sh. 37.) has stated his reasons for considering as Trochi, all the species which have horny opercula; and as Turbines, all those which have testaceous opercula. Fig. 358 to 360. The Trochi are found in all climates.TROPÆUM. Sow.Crioceratites.TROPHON. Montf.MurexMagellanicus, Auct. and several other species which belong more properly to Fusus than to Murex.TRUMPET SHELL. A large species of Triton (variegatus), used by natives of South Sea Islands as a trumpet, to call warriors and herds of cattle together. It answers the purpose tolerably well, producing a very sonorous blast.TRUNCATED. (truncus, cut short.) Terminating abruptly, as it were cut short.Ex.Solenensis, fig. 60.TRUNCATULANA. D'Orb. A genus of microscopic Foraminifera.TRUNCATELLA. Risso. A genus composed of several species of land shells which have been confounded by some authors with Cyclostoma. The genus is thus described: "Shell turriculated, cylindrical, decollated or truncated at the apex, no epidermis; aperture oval, short, with lips continuous, simple."Ex.Truncatella truncatulina, Lowe, Zool. Journ. t. 5. p. 80. Our plates, fig. 520, 521. It is found on the shores of Britain, the Mediterranean, and West Indies.TUBA. Lea. A genus of small fossil shells, described as resembling Turbo, but with the aperture more like that of Melania. Lea. Contrib. Geol.TUBERCLE. (tuberculus.) A small swelling excrescence, or knob.TUBERCULATED. Having a number of small lumps or pimples, as Turrilites, fig. 483.TUBICINELLA. Lam. (Tubicen, a trumpeter.)Order, Sessile Cirripedes, Lam.—Descr.A cylindrical tube, composed of six elongated valves jointed together side by side, striated longitudinally, surrounded by concentric rings; aperture circular, enclosed by an operculum of four valves, placed perpendicularly in an epiphragm.—Obs.The Tubicinellæ are found with nearly the whole shell buried in the thick skin of the whale. T. Balænarum.TUBICOLARIA. Lam. (Tuba, a tube;cola, an inhabitant.) A family of the order Conchifera Dimyaria, Lam. consisting of bivalves soldered as it were within, or connected with, a testaceous tube. The genera contained in this family may be thus distinguished.

TRIDENTATE. (Tridentatus.) Having three teeth, or salient points.Ex.Hyalæa tridentata, fig. 226.

TRIGONA. Schum.? Triangular species ofCytherea, such as C. lævigata, Triplas corbicula, ventricosa, bicolor, &c. Fig. 117b.

TRIGONACEA. Lam. A family belonging to the order Conchifera Dimyaria, containing the genera Trigonia and Castalia, the latter of which ought to be removed to the Nayades. Fig. 139, 140.

TRIGONAL. Triangular, having three sides.

TRIGONELLA. Humph.Mactra, Auct.

TRIGONIA. Brug. (τριγωνον,trigonon, triangular.)Fam.Trigonata, Lam. Camacea, Bl.—Descr.Equivalve, inequilateral, transverse, sub-trigonal, costated and granulated without, pearly and iridescent within, denticulated on the inner margin, rounded anteriorly, truncated posteriorly; hinge with four oblong, compressed, diverging teeth in one valve, receiving between their grooved sides, two similar teeth in the other; ligament external, thick; muscular impressions two in each valve.—Obs.Only one recent species of this marine genus is known, the T. pectinata, which comes from New Holland; and was formerly so rare, that a much worn odd valve has been sold for a considerable sum. It is of a brilliant pearly texture within, tinged with purple or golden brown. Fossil species occur in Lias, upper and lower Oolite, and Green-sand. T. Pectinata, fig. 139.

TRIGONOSEMUS. König. A genus composed of species ofTerebratula, Auct. which have one valve produced into a beak, perforated, or as it were truncated at the apex. T. lyra, fig. 208, differing from Terebratula lyra, Lam.

TRIGONOSTOMA. A sub-genus of Helix, with a trigonal aperture. Gray's Turton, p. 139.

TRIGONOTRETA. König. A genus composed of species of Terebratula, Auct. which have the hinge of the larger valve produced into a triangular disc, divided by a triangular foramen in the centre. Spirifer, Sowerby, belongs to this genus. Fig. 214, 215.

TRILOBATE. (Τρειςthree;λοβος, division, lobe.) Divided into three lobes or principal parts. Ex. Malleus, Fig. 165.

TRILOCULINA. D'Orbigny. A genus of microscopic Foraminifera.

TRIPARTITE. (Tripartitus) composed of or divided into three separate parts.

TRIPHORA, or TRISTOMA. Deshayes. A genus composed of small reversed species ofCerithium, Auct. which have the anterior canal closed at the anterior of the aperture, but opened at the extremity, and a small tubular opening on the upper part of the whorls, making three openings on the body whorl. This genus stands in the same relation to Cerithium as the Typhis to Murex. Fig. 375 in the old plates, and fig. in the new plates.

TRIPLEX. Humph.Murex, Linn.

TRIPLODON. Spix.Hyria, Auct.

TRIPTERA. Quoy et Gaimard,Cuviera, Fer. Described in the Voyage de la Coquille, and represented as a molluscous animal destitute of a shell.

TRIQUETRA. Bl. Triangular species ofVenusAuct.

TRISIS. Oken.Arcatortuosa, Auct.

TRISTOMA. Described asTriphora.

TRITON. Auct.Fam.Siphonostomata, Bl. Canalifera, Lam.—Descr.Oblong or oval, thick, ribbed or tuberculated, with discontinuous varices placed at irregular distances; spire prominent, mammillated; aperture round or oval, terminating anteriorly in a generally long, slightly raised canal; columellar lip granulated or denticulated; outer lip thickened, reflected, generally denticulated within; epidermis rough; operculum horny.—Obs.However nearly allied the Tritons may appear to be to the Murices and Ranellæ there are still to be traced in the shells of each of those genera, several constant and well marked distinctions, by which they maybe at once recognized. In the Ranellæ, the varices run in two rows along the spire; in the Murices, they form three or more rows; but in the Tritons, they do not follow each other,i.e.they do not occur in the same part of each volution. The large species of Triton, are sometimes used as trumpets. The Tritons are brought from the Mediterranean, Ceylon, the East and West Indies, and South Seas. Fig. 398 to 401.

TRITONIDEA. Sw. A genus of "Buccininæ," Sw. thus described: "Shell bucciniform, but the basal half is narrowed, and the middle more or less ventricose; spire and aperture equal. Pillar at the base with two or three obtuse and very transverse plaits, not well defined; outer lip internally crenated and with a superior siphon; inner lip wanting, or rudimentary." This genus is the same as the one first distinguished by Mr. Gray under the name of Pollia. We do not regret the discovery made by Mr. Swainson of that name being previously occupied for a genus of Lepidopterous Insects. Fig. 415, represents Tritonidea articularis. (Pollia, Gray.)

TRIVIA. Gray. A genus composed of those small species ofCypræa, Auct. which are characterized by small ridges on the dorsal surface, and have the anterior of the columella internally concave and ribbed. C. Pediculus. Auct. fig. 449, 450.

TROCHATELLA. Sw. A sub-genus of Helicinæ, consisting of those species which are acute and trochiform.

TROCHIA. Sw. A genus of the family Buccininæ, thus described: "shape intermediate between Purpura and Buccinum; whorls separated by a deep groove; inner lip when young, depressed, when adult, thickened, convex and striated; basal canal very small. T. sulcatus. E. M. 422. f. 4." Sw. Malac. p. 300.

TROCHIDON. Sw. A sub-genus of "Trochinæ," Sw. Lardn. Cyclop. Malac. p. 351.

TROCHILÆA. Sw.?Pileolus, Auct.

TROCHURUS. Humph.Monodonta. Lam.

TROCHUS. Auct. (A top.)Fam.Turbinacea, Lam. Goniostomata, Bl.—Descr.Turbinated, thick, striated, tuberculated or smooth; spire elevated, conical, consisting of numerous whorls; under surface discoid; aperture more or less depressed in an oblique direction, generally angular; columella arcuated, more or less prominent at its union with the outer lip, contiguous to the axis of the shell; operculum horny, orbicular, with numerous whorls.—Obs.Lamarck distinguished this genus from Turbo by the general form, which is more conical, and the aperture, which is angulated, while that of Turbo is rounded. Monodonta or Odontis is only separated on account of the notch at the termination of the columella. But these characters glide so imperceptibly from one genus to the other, that there is no line of demarcation to be found but in the operculum. Accordingly, Sowerby (in Gen. of Sh. 37.) has stated his reasons for considering as Trochi, all the species which have horny opercula; and as Turbines, all those which have testaceous opercula. Fig. 358 to 360. The Trochi are found in all climates.

TROPÆUM. Sow.Crioceratites.

TROPHON. Montf.MurexMagellanicus, Auct. and several other species which belong more properly to Fusus than to Murex.

TRUMPET SHELL. A large species of Triton (variegatus), used by natives of South Sea Islands as a trumpet, to call warriors and herds of cattle together. It answers the purpose tolerably well, producing a very sonorous blast.

TRUNCATED. (truncus, cut short.) Terminating abruptly, as it were cut short.Ex.Solenensis, fig. 60.

TRUNCATULANA. D'Orb. A genus of microscopic Foraminifera.

TRUNCATELLA. Risso. A genus composed of several species of land shells which have been confounded by some authors with Cyclostoma. The genus is thus described: "Shell turriculated, cylindrical, decollated or truncated at the apex, no epidermis; aperture oval, short, with lips continuous, simple."Ex.Truncatella truncatulina, Lowe, Zool. Journ. t. 5. p. 80. Our plates, fig. 520, 521. It is found on the shores of Britain, the Mediterranean, and West Indies.

TUBA. Lea. A genus of small fossil shells, described as resembling Turbo, but with the aperture more like that of Melania. Lea. Contrib. Geol.

TUBERCLE. (tuberculus.) A small swelling excrescence, or knob.

TUBERCULATED. Having a number of small lumps or pimples, as Turrilites, fig. 483.

TUBICINELLA. Lam. (Tubicen, a trumpeter.)Order, Sessile Cirripedes, Lam.—Descr.A cylindrical tube, composed of six elongated valves jointed together side by side, striated longitudinally, surrounded by concentric rings; aperture circular, enclosed by an operculum of four valves, placed perpendicularly in an epiphragm.—Obs.The Tubicinellæ are found with nearly the whole shell buried in the thick skin of the whale. T. Balænarum.

TUBICOLARIA. Lam. (Tuba, a tube;cola, an inhabitant.) A family of the order Conchifera Dimyaria, Lam. consisting of bivalves soldered as it were within, or connected with, a testaceous tube. The genera contained in this family may be thus distinguished.

1.Aspergillum.Valves fixed, tube perforated and fringed. Fig. 44.2.Teredina.Valves fixed, prominent, tube closed at one end. Fossil. Fig. 46, 47.3.Clavagella.One valve fixed, the other free. Fig. 45.4.Teredo.Both valves free, tube open at both ends. Fig. 48, 49.5.Fistulana.Valves free, tube closed at one end, straight, long. Fig. 53, 54.6.Gastrochæna.Valves free, tube closed at one end, short, bulbous. Fig. 52.

1.Aspergillum.Valves fixed, tube perforated and fringed. Fig. 44.

2.Teredina.Valves fixed, prominent, tube closed at one end. Fossil. Fig. 46, 47.

3.Clavagella.One valve fixed, the other free. Fig. 45.

4.Teredo.Both valves free, tube open at both ends. Fig. 48, 49.

5.Fistulana.Valves free, tube closed at one end, straight, long. Fig. 53, 54.

6.Gastrochæna.Valves free, tube closed at one end, short, bulbous. Fig. 52.

TUBIVALVES. Bl. Shells composed of two valves connected in a tube, corresponding with the family Tubicolæ of Lamarck.TULIPARIA. Sw. A sub-genus of "Coronaxis," Sw. Lardn. Cyclop. Malac. p. 311.TURBINACEA. Bl. The sixth family of Polythalamacea, Bl. containing the genera Cibicides and Rosallites, microscopic Foraminifera.TURBINACEA. Lam. A family of the first section of the order Trachelipoda, Lam. containing the following genera.

TUBIVALVES. Bl. Shells composed of two valves connected in a tube, corresponding with the family Tubicolæ of Lamarck.

TULIPARIA. Sw. A sub-genus of "Coronaxis," Sw. Lardn. Cyclop. Malac. p. 311.

TURBINACEA. Bl. The sixth family of Polythalamacea, Bl. containing the genera Cibicides and Rosallites, microscopic Foraminifera.

TURBINACEA. Lam. A family of the first section of the order Trachelipoda, Lam. containing the following genera.

1.Solarium.With umbilicus reaching to the apex; includingBifrontiaandOrbis. Fig. 353 to 356.2.Rotella.A callosity on the under side. Fig. 357.3.Phasianella.Oval; operculum shelly. Fig. 367.4.Planaxis.Columellar lip flat; aperture notched. Fig. 365.5.Turbo.Top-shaped; mouth generally round; operculum shelly. Fig. 368.6.Trochus.Top-shaped; mouth generally angulated; operculum horny, consisting of many whorls; includingElenchus. Fig. 358, 359, 361.7.Margarita.Operculum horny, consisting of few whorls; pearly. Fig. 362.8.Littorina.Similar, not pearly; includingAssiminnea. Fig. 363, 363*.9.Phorus.Attaching dead shells, stones, &c. Fig. 360.10.MonodontaorOdontis. A notch and prominent point at the lower part of the aperture. Fig. 366.11.Lacuna.With an umbilicus. Fig. 364.12.Turritella.Elongated, screw-shaped. Fig. 369 to 371.

1.Solarium.With umbilicus reaching to the apex; includingBifrontiaandOrbis. Fig. 353 to 356.

2.Rotella.A callosity on the under side. Fig. 357.

3.Phasianella.Oval; operculum shelly. Fig. 367.

4.Planaxis.Columellar lip flat; aperture notched. Fig. 365.

5.Turbo.Top-shaped; mouth generally round; operculum shelly. Fig. 368.

6.Trochus.Top-shaped; mouth generally angulated; operculum horny, consisting of many whorls; includingElenchus. Fig. 358, 359, 361.

7.Margarita.Operculum horny, consisting of few whorls; pearly. Fig. 362.

8.Littorina.Similar, not pearly; includingAssiminnea. Fig. 363, 363*.

9.Phorus.Attaching dead shells, stones, &c. Fig. 360.

10.MonodontaorOdontis. A notch and prominent point at the lower part of the aperture. Fig. 366.

11.Lacuna.With an umbilicus. Fig. 364.

12.Turritella.Elongated, screw-shaped. Fig. 369 to 371.

TURBINATED. (Turbo, a top,) Top-shaped. The term is applied generally to those shells which are large at one extremity, and narrow to a point at the other.Ex.Trochus, fig. 358; Turbinellus, fig. 382.TURBINELLUS. Auct. (A little top.)Fam.Canalifera, Lam. Siphonostomata, Bl.—Descr.Turbinated, thick, wide near the apex, generally tuberculated; spire short, depressed, mammillated; aperture rather narrow, terminating anteriorly in an open canal; outer lip thickened within; columella having from three to five prominent, compressed, transverse folds. The species of this genus are mostly tropical.—Obs.The Turbinelli are a well marked genus of marine shells, the species of which are numerous. No fossil species are known. The genus Cancellaria makes the nearest approach to Turbinellus in some characters, but may be distinguished by the roundness of its form, the raised lines inside the outer lip, and the obliquity of the folds on the columella. Fig. 382 to 384.TURBO. Auct. (A top.)Fam.Cricostomata, Bl. Turbinacea, Lam.—Descr.Turbinated, solid, ventricose, generally grooved or tuberculated; spire short, pointed; aperture generally rounded, sub-effuse anteriorly, entire; operculum shelly, solid, incrassated on the outer side, horny and sub-spiral on the inner side. The Turbines are mostly tropical.—Obs.The only certain means of distinguishing this extensive genus of marine shells from Trochus, is the operculum, which in the latter genus is horny, spiral, and composed of a great number of whorls. The Trochi, however, are in general more conical, and flatter at the under side of the whorls, and this constitutes Lamarck's distinction between the genera. T. setosus, fig. 368.TURGID. (Turgidus.) Puffed up, swollen, inflated. This term is applied synonymously with Ventricose.TURRICULA. Humph.Melania, Auct.TURRICULACEA. Bl. The seventh family of the Order Polythalamacea, Bl. containing the genus Turrilites, fig. 483.TURRILITES. Lam. (Turris, a tower;λιθος, a stone.)Fam.Turriculacea, Lam. Ammonacea, Bl.—Descr.Chambered, turrited, spiral; septa sinuous and lobate, perforated by a siphon; aperture rounded, with the outer lip expanded. This genus, which is distinguished from the other Ammonacea by having the spire produced,i. e.not being convolute, consists of several species, occurring only in chalk-marl. Fig. 483.TURRIS. Montf. A genus composed of those species ofMitra, Auct. which have the whorls angulated, with the aperture lengthened and undulated.TURRITED. The spire of an univalve shell is said to beturritedwhen the whorls of which it is composed are regulated so as to have the appearance of little turrets rising above each other, as in Mitra, fig. 431.TURRITELLA. Lam. (A little tower.)Fam.Turbinacea, Lam. Cricostomata, Bl.—Descr.Turrited, elongated, generally grooved spirally; spire pointed, consisting of numerous whorls; aperture rounded or angulated; inner and outer lips thin, confluent anteriorly; operculum horny.—Obs.The shells composing this well defined genus, are commonly called screws, a name to which the spiral grooves of most of the species seems to entitle them. Fig. 370, T. imbricata.TYMPANOSTOMA. Schum. (Timbrel mouth.)Potamis, Brongn.TYPHIS. Montf. A genus composed ofMurextubifer, Auct. and other similar species, which have the canal closed and a perforated tube between each varix on the angulated part of the whorls. Besides the fossil species originally described, there are now five species known, which are figured in part 200, of the Conchological Illustrations by the Author. Typhis tubifer, fig. 397.ULTIMUS. Montf. (The last.) A genus composed ofOvulumgibbosum, Auct. fig. 443, and other species in which the canals are not distinctly defined, nor elongated. This fanciful name is given to the genus on account of its being described in the last page of the book.UMBILICATED. (Umbilicatus.) Having an umbilicus, as Nautilus umbilicatus.UMBILICUS. (A navel.) The hollow formed in spiral shells when the inner side of the volutions do not join each other, so that the axis is hollow. The umbilicus is marked with the letter u in Helix algira, fig. 279. The term is also used to express any small, neat, rounded hollow.UMBO. (The boss of a buckler or shield.) The point of a bivalve shell above the hinge, which constitutes the apex or nucleus of each valve, from which the longitudinal rays diverge, and the lines of growth, commencing at the minutest circle, descend in gradually enlarging concentric layers to the outer margin. The umbones will be marked with the letteru, in Cytherea, fig. 117.UMBRELLA. (A little shade.)Fam.Semiphyllidiana, Lam. Patelloidea, Bl.—Descr.Patelliform, sub-orbicular, compressed, rather irregular; apex slightly raised, placed near the centre; margin acute; internal surface with a central, callous, coloured disc, surrounded by a continuous, irregular muscular impression.—Obs.This genus is known from Patella, by its continuous muscular impression. It is commonly called the Chinese Umbrella shell. There are but two species at present known; the U. Mediterranea, and the U. Indica, fig. 233.UNDATED. (Unda, a wave.) Waved.UNDULATED. (Undulatus.) Minutely waved.UNGUICULATED. (Unguis, a nail or hoof.) An unguiculated operculum is one in which the layers are disposed laterally, and the nucleus constitutes part of the outer edge.UNGULINA. Daud. (Ungula, a nail or claw.)Fam.Mactracea, Lam. Conchacea, Bl.—Descr.Equivalve, sub-orbicular, sub-equilateral, with margins entire, simple, closed all round; hinge with one short, sub-divided cardinal tooth in each valve, and a very minute additional tooth in one valve, an oblong ligamentary pit divided into two portions, one of which receives the cartilage, the external ligament is immediately below the umbones; muscular impressions, two in each valve, oblong; impression of the mantle entire. U. transversa, fig. 88. Coast of Africa.UNI-AURICULATED. Having oneAuricle. SeeAuriculated.UNICORNUS. Montf.Monoceros, Auct.UNIO. (A pearl.)Fam.Nayades, Lam. Submytilacea, Bl.—Descr.Inequilateral, equivalve, regular, free, pearly within, covered by a smooth epidermis without; umbones prominent, generally corroded; muscular impressions two in each valve, lateral, distant; the anterior composed of several small divisions; hinge varying in age, species, and individuals.—Obs.The above description is framed so as to include all the genera of the Lamarckian Nayades, together with Castalia, which are placed in the family Trigonacea, they are all fresh-water shells, commonly called fresh-water muscles. The distinctions of the various genera into which they have been divided, will be found in their respective places, and under the name Nayades. They are all represented in figures 140 to 152. Of these fig. 145 to 148, are more generally considered as forming the genus Unio.UNIOPSIS. Sw. A sub-genus of Alasmodon. Sw. p. 382.UNIVALVE. (Unus, one;valva, valve.) A shell consisting of a single piece, as distinguished from Bivalves and Multivalves, which are composed of two or more principal pieces. Spiral shells having an operculum, are called sub-bivalves by some authors.UPPER-VALVE. The free valve in attached bivalves.UVIGERINA. D'Orb. A genus of microscopic Foraminifera.VAGINA. Megerle.Solenvagina, Auct.VAGINULA. (A little sheath, the husk of corn.)Class, Pteropoda, Lam.—Descr.Pyramidal, slightly inflated in the centre, thin, fragile; aperture oblong, with the edges turned slightly outwards.—Obs.The little shells of this genus, which are only known in a fossil state, differ from Cuvieria in being pointed at the extremity. Found in the tertiary beds of Bordeaux. V. Daudinii, fig. 225.VAGINULINA. D'Orb. A genus of microscopic Foraminifera.VALVATA. Müll.Fam.Peristomata, Lam. Cricostomata, Bl.—Descr.Thin, turbinated; spire short, composed of from three to six rounded whorls; aperture circular; peritreme acute, entire; operculum horny, spiral.—Obs.This genus of small shells resembles Cyclostoma, from which the recent species may be known by the horny texture of the external surface, being fresh-water shells. The fossils of course belong to the fresh-water formations. V. piscinalis, fig. 322. Europe and North America.VALVES. (Valva, a door, a folding piece.) The two pieces composing a bivalve shell, which close upon each other, turning upon a hinge consisting of a ligament, cartilage, and teeth. SeeBivalve,Multivalve, andUnivalve.VALVULINA. D'Orb. A genus of microscopic Foraminifera.VARIX. (A swelling vein.) A varix is formed on the outer surface of a spiral shell, by the thickened, reflected edge of a former aperture, after fresh deposits of testaceous matter have increased the size by adding to the growth of the shell beyond it. In this manner there are frequently many varices, or edges of former apertures, in various parts of the spire and the body whorl. They are sometimes placed at regular distances from each other, as in Harpa, fig. 419; sometimescontinuous, as in Ranella, fig. 394; sometimesdiscontinuous, as in Triton, fig. 398; sometimesramose, as in Murex, fig. 395; sometimessimple, as in Scalaria, fig. 351; sometimesspinose, as in Murex spinosus. The termvarixhas also been applied to any swelling ridge, such as that on the lower part of the columella of Ancillaria, fig. 456.VELATES. Montf.Neritinaperversa, Auct. Fig. 326.VELLETIA. Gray? A genus described as differing fromAncylusin being dextral.Velletialacustris,Ancyluslacustris, Auct. fig. Sowerby Gen. fig. 2.VELUTINA. Auct.Fam.Macrostomata, Lam.—Descr.Sub-globose, covered with a velvety epidermis; spire short, composed of two rapidly enlarged ventricose whorls; aperture large, sub-ovate; peritreme thin, entire, separated from the last whorl; columella tortuous, thin.—Obs.This shell does not resemble any other genus in the family. Fig. 337. Northern Seas.VENERICARDIA. Lam. A genus composed of the shorter species of Cardita.VENERIRUPIS. Lam. (FromVenusandrupis, a rock.) The oblong species of Venus Auct. which live in cavities of rocks and stones. This genus is united by Sowerby with some other species of Venus under the name Pullastra. V. Vulgaris, fig. 97.VENTRAL. (Venter, the belly.) The margin of a bivalve shell opposite the hinge. The under valve in Brachiopodous bivalves is the ventral valve. The ventral surface of an univalve spiral shell is that which faces the observer when the aperture is placed towards him. The ventral part of the whorls of symmetrical convolute shells, is the inner part, that which is nearest to the spire.VENTRAL SIPHON. In symmetrical convolute univalves, is one placed near the inner edge of the whorls.VENTRICOSE. (Ventricosus.) Swelled, rounded out, (bombé Fr.) as Harpa ventricosa, fig. 419.VENUS. Auct. (Goddess of Beauty.)Fam.Marine Conchacea, Lam. Conchacea, Bl.—Descr.Equivalve, inequilateral, sub-globose, sub-ovate, transverse, externally rugose, striated, ribbed, cancellated or smooth; margins entire, simple, close; hinge with three more or less distinct cardinal teeth, diverging from the umbones in each valve; muscular impressions two, lateral, distant; palleal impressions sinuated posteriorly; ligament external.—Obs.This extensive genus, including some bivalves of splendour and beauty, justifying the name given to it, may be known from Cytherea by the absence of a lateral tooth, which is found near the cardinal teeth in the latter. Artemis is distinguished not only by its beautiful form, but by the deep angular sinus in the palleal impression. Fig. 119, 119a. Found mostly in temperate and tropical climates.VERMETUS. Adanson.Fam.Scalariana, Lam. Cricostomata, Bl.—Descr.Spiral at the apex, irregularly twisted towards the aperture; aperture round, small.—Obs.This shell resembles the Serpulæ in general appearance, although it is regularly spiral near the apex. The animal is known to be a true mollusc, rather nearly allied to that of the genus Dentalium, which is also placed wrongly in the Lamarckian system. Vermetus Lumbricalis, fig. 345. Coast of Africa.VERMICULAR. (Vermicularis.) Worm-shaped, tubular, serpentine.Ex.Vermilia triquetra, fig. 7.VERMICULARIA. Lam.Vermetus, Adanson; afterwardsVermetus, Lam.VERMILIA. Lam. A genus composed of species of Serpula, which are attached by the whole length of the shell, no part being free. Vermilia triquetra, fig. 7.VERTEBRALINA. D'Orb. A genus of microscopic Foraminifera.VERTEX. Apex.VERTIGO. Müll.Fam.Colimacea, Lam.—Descr.Cylindrically fusiform, sinistral, hyaline; aperture marginated, sinuated, denticulated on the inner edge; peristome sub-reflected.—Obs.This genus of minute land shells, resembles Pupa, but is a reversed, hyaline shell. Vertigo pusilla, fig. 293. Europe.VERRUCA. Schum.Clitia, Leach.VESICA. Sw. A sub-genus of Bulinus, Sw. p. 360.VEXILLA. Sw. A genus of "Nassinæ," Sw. thus described: "General shape ofPurpura, the inner lip flattened and depressed; the outer, when adult, thickened, inflected and toothed; aperture wide; pictaSw.Chem. pl. 157, f. 1504-5." Sw. Malac. p. 300.VIRGULINA. D'Orb. A genus of microscopic Foraminifera.VITRELLA. Sw. A sub-genus of "Bullinæ," Sw. Lardn. Cyclop. Malac. p. 360.VITRINA. Drap. (Vitreus, glassy.)Fam.Limacinea, Lam. and Bl.—Descr.Ovate, thin, glassy, fragile; spire short; last whorl large; aperture wide, transverse; peritreme simple; columella spiral, linear.—Obs.This genus of land-shells is not known in a fossil state. The recent species are found among moss and grass, in shady situations. De Ferussac has divided this genus into Helicolimax, fig. 263, and Helixarion, fig. 262.VITULARIA. Sw. A genus of "Muricinæ," Sw. thus described: "General habit ofMuricidea, but the inner lip is depressed and flattened as in thePurpurinæ; varices simple, nearly obsolete. Tuberculata, Sw. En. M. 419. fig. 1. (Murex vitulinus, Auct.)" Sw. p. 297.VIVIPARA. A generic name given by Montfort, and retained by some authors forPaludina, Lam. on account of the animals beingviviparous, i. e. the young being perfectly formed before they leave the ovaries.VIVIPAROUS. SeeVivipara.VOLUTA. Auct. (Volvo, to revolve.)Fam.Columellaria, Lam. Angyostomata, Bl.—Descr.Sub-ovate, rather angulated, thick, generally tuberculated, smooth; spire short, conical, with a mammillated apex; aperture generally angulated, large, terminating anteriorly in a deep notch; columella smooth, with several plaits, of which the lowest is the largest; outer lip thickened within.—Obs.The genus Voluta, as left by Linnæus, is only characterized by the folds on the columella, and includes many shells which, although they agree in this respect with the genus, are yet quite opposite to each other in all other characters. Thus the Auriculæ, which are land shells, and have the aperture entire, are mixed up with others which are marine, and have a canal, as Turbinellæ, and the Fasciolariæ, and others which have merely a notch, as the true Volutes. This genus, as it is circumscribed at present, includes a great number of beautiful shells, most of which are rich in colouring.CymbaandMelohave been separated by Mr. Broderip from the genusVolutaof Lamarck, for reasons stated in their respective descriptions. Fig. 443.VOLVARIA. Lam. (Volva, a shuttle.)Fam.Columellaria, Lam.—Descr.Cylindrical, convolute, spirally striated; spire very short, nearly hidden; aperture narrow, as long as the whole shell; columella with three oblique plaits; outer lip dentated.—Obs.The Volvaria are only known in a fossil state, and resemble some species of Bulla in general form, but are distinguished by the plaits on the columella. Fig. 439, V. concinna.VOLUTELLA. Sw. (A little volute.) A genus composed of those species ofMarginella, Auct. which have the spire concealed, and the aperture smooth within. Fig. 438,Persiculaof Schumacher.VOLUTILITHES. Sw. (Voluta, andλιθος,lithos, a stone.) A genus composed of some fossil species of Voluta, which have the plaits on the pillar generally numerous, indistinct, and sometimes wanting altogether, with a pointed spire. Fig. 436, V. spinosa.VOLUTION. SeeWhorl.VORTICIALIS. Lam. A genus of microscopic Foraminifera.VULSELLA. Lam. (A little tongue.)Fam.Ostracea, Lau. Margaritacea, Bl.—Descr.Equivalve, irregular, longitudinal, compressed, oblong; umbones separated by a slight area in both valves; hinge with a large pit in the centre, containing the cartilage, the ligament being spread over the areas; muscular impressions, one on each valve, sub-central, oblong.—Obs.This genus differs from Ostræa in the equality of the valves, and in having a hollow pit in the hinge for the cartilage. Vulsella lingulata, fig. 185.WATERING-POT. Aspergillum, fig. 44, commonly so called on account of the resemblance of its perforated termination to that of the spout of a watering-pot.WENTLE TRAP. Scalaria pretiosa, commonly so called.WHORL. A complete turn or revolution round the imaginary axis of a spiral shell. The last whorl is called thebody-whorl. The whorls are described asnon-contiguous, when they do not touch each other;continuous, in the opposite case.Depressedwhen they are flat. They areangulated,heeled, or coronated;distinct, or indistinct. They are sometimes, as in Cypræa, hidden by the last whorl.XYLOPHAGA. Sow. (ξυλον,zylon, wood;φαγω,phago, to eat.)Fam.Tubiscolæ, Lam.—Descr.Equivalve, globose, closed at the back; with a large, angular hiatus in front; hinge with a small curved tooth advancing from beneath the umbones in each valve.—Obs.This shell, which is found in a cylindrical cavity, eaten in wood by the animal, resembles Teredo, but has not the shelly tube, nor the posterior hiatus. X. dorsalis, fig. 50, 51.XYLOTRYA. Leach.Xylophaga, Sow.ZONITES. Montf. A genus formed of Helix Algira, and other similar species with depressed spires and large umbilici; included in the sub-genus Helicella. Fig. 279.ZUA. Leach. A genus described as differing from Bulinus in having a polished epidermis, and a thickened, not reflected lip. Zua lubrica, B. lubricus, Auct.ZURAMA. Leach. A sub-genus of Helix. H. pulchella, Auct. Gray's Turton, p. 41.

TURBINATED. (Turbo, a top,) Top-shaped. The term is applied generally to those shells which are large at one extremity, and narrow to a point at the other.Ex.Trochus, fig. 358; Turbinellus, fig. 382.

TURBINELLUS. Auct. (A little top.)Fam.Canalifera, Lam. Siphonostomata, Bl.—Descr.Turbinated, thick, wide near the apex, generally tuberculated; spire short, depressed, mammillated; aperture rather narrow, terminating anteriorly in an open canal; outer lip thickened within; columella having from three to five prominent, compressed, transverse folds. The species of this genus are mostly tropical.—Obs.The Turbinelli are a well marked genus of marine shells, the species of which are numerous. No fossil species are known. The genus Cancellaria makes the nearest approach to Turbinellus in some characters, but may be distinguished by the roundness of its form, the raised lines inside the outer lip, and the obliquity of the folds on the columella. Fig. 382 to 384.

TURBO. Auct. (A top.)Fam.Cricostomata, Bl. Turbinacea, Lam.—Descr.Turbinated, solid, ventricose, generally grooved or tuberculated; spire short, pointed; aperture generally rounded, sub-effuse anteriorly, entire; operculum shelly, solid, incrassated on the outer side, horny and sub-spiral on the inner side. The Turbines are mostly tropical.—Obs.The only certain means of distinguishing this extensive genus of marine shells from Trochus, is the operculum, which in the latter genus is horny, spiral, and composed of a great number of whorls. The Trochi, however, are in general more conical, and flatter at the under side of the whorls, and this constitutes Lamarck's distinction between the genera. T. setosus, fig. 368.

TURGID. (Turgidus.) Puffed up, swollen, inflated. This term is applied synonymously with Ventricose.

TURRICULA. Humph.Melania, Auct.

TURRICULACEA. Bl. The seventh family of the Order Polythalamacea, Bl. containing the genus Turrilites, fig. 483.

TURRILITES. Lam. (Turris, a tower;λιθος, a stone.)Fam.Turriculacea, Lam. Ammonacea, Bl.—Descr.Chambered, turrited, spiral; septa sinuous and lobate, perforated by a siphon; aperture rounded, with the outer lip expanded. This genus, which is distinguished from the other Ammonacea by having the spire produced,i. e.not being convolute, consists of several species, occurring only in chalk-marl. Fig. 483.

TURRIS. Montf. A genus composed of those species ofMitra, Auct. which have the whorls angulated, with the aperture lengthened and undulated.

TURRITED. The spire of an univalve shell is said to beturritedwhen the whorls of which it is composed are regulated so as to have the appearance of little turrets rising above each other, as in Mitra, fig. 431.

TURRITELLA. Lam. (A little tower.)Fam.Turbinacea, Lam. Cricostomata, Bl.—Descr.Turrited, elongated, generally grooved spirally; spire pointed, consisting of numerous whorls; aperture rounded or angulated; inner and outer lips thin, confluent anteriorly; operculum horny.—Obs.The shells composing this well defined genus, are commonly called screws, a name to which the spiral grooves of most of the species seems to entitle them. Fig. 370, T. imbricata.

TYMPANOSTOMA. Schum. (Timbrel mouth.)Potamis, Brongn.

TYPHIS. Montf. A genus composed ofMurextubifer, Auct. and other similar species, which have the canal closed and a perforated tube between each varix on the angulated part of the whorls. Besides the fossil species originally described, there are now five species known, which are figured in part 200, of the Conchological Illustrations by the Author. Typhis tubifer, fig. 397.

ULTIMUS. Montf. (The last.) A genus composed ofOvulumgibbosum, Auct. fig. 443, and other species in which the canals are not distinctly defined, nor elongated. This fanciful name is given to the genus on account of its being described in the last page of the book.

UMBILICATED. (Umbilicatus.) Having an umbilicus, as Nautilus umbilicatus.

UMBILICUS. (A navel.) The hollow formed in spiral shells when the inner side of the volutions do not join each other, so that the axis is hollow. The umbilicus is marked with the letter u in Helix algira, fig. 279. The term is also used to express any small, neat, rounded hollow.

UMBO. (The boss of a buckler or shield.) The point of a bivalve shell above the hinge, which constitutes the apex or nucleus of each valve, from which the longitudinal rays diverge, and the lines of growth, commencing at the minutest circle, descend in gradually enlarging concentric layers to the outer margin. The umbones will be marked with the letteru, in Cytherea, fig. 117.

UMBRELLA. (A little shade.)Fam.Semiphyllidiana, Lam. Patelloidea, Bl.—Descr.Patelliform, sub-orbicular, compressed, rather irregular; apex slightly raised, placed near the centre; margin acute; internal surface with a central, callous, coloured disc, surrounded by a continuous, irregular muscular impression.—Obs.This genus is known from Patella, by its continuous muscular impression. It is commonly called the Chinese Umbrella shell. There are but two species at present known; the U. Mediterranea, and the U. Indica, fig. 233.

UNDATED. (Unda, a wave.) Waved.

UNDULATED. (Undulatus.) Minutely waved.

UNGUICULATED. (Unguis, a nail or hoof.) An unguiculated operculum is one in which the layers are disposed laterally, and the nucleus constitutes part of the outer edge.

UNGULINA. Daud. (Ungula, a nail or claw.)Fam.Mactracea, Lam. Conchacea, Bl.—Descr.Equivalve, sub-orbicular, sub-equilateral, with margins entire, simple, closed all round; hinge with one short, sub-divided cardinal tooth in each valve, and a very minute additional tooth in one valve, an oblong ligamentary pit divided into two portions, one of which receives the cartilage, the external ligament is immediately below the umbones; muscular impressions, two in each valve, oblong; impression of the mantle entire. U. transversa, fig. 88. Coast of Africa.

UNI-AURICULATED. Having oneAuricle. SeeAuriculated.

UNICORNUS. Montf.Monoceros, Auct.

UNIO. (A pearl.)Fam.Nayades, Lam. Submytilacea, Bl.—Descr.Inequilateral, equivalve, regular, free, pearly within, covered by a smooth epidermis without; umbones prominent, generally corroded; muscular impressions two in each valve, lateral, distant; the anterior composed of several small divisions; hinge varying in age, species, and individuals.—Obs.The above description is framed so as to include all the genera of the Lamarckian Nayades, together with Castalia, which are placed in the family Trigonacea, they are all fresh-water shells, commonly called fresh-water muscles. The distinctions of the various genera into which they have been divided, will be found in their respective places, and under the name Nayades. They are all represented in figures 140 to 152. Of these fig. 145 to 148, are more generally considered as forming the genus Unio.

UNIOPSIS. Sw. A sub-genus of Alasmodon. Sw. p. 382.

UNIVALVE. (Unus, one;valva, valve.) A shell consisting of a single piece, as distinguished from Bivalves and Multivalves, which are composed of two or more principal pieces. Spiral shells having an operculum, are called sub-bivalves by some authors.

UPPER-VALVE. The free valve in attached bivalves.

UVIGERINA. D'Orb. A genus of microscopic Foraminifera.

VAGINA. Megerle.Solenvagina, Auct.

VAGINULA. (A little sheath, the husk of corn.)Class, Pteropoda, Lam.—Descr.Pyramidal, slightly inflated in the centre, thin, fragile; aperture oblong, with the edges turned slightly outwards.—Obs.The little shells of this genus, which are only known in a fossil state, differ from Cuvieria in being pointed at the extremity. Found in the tertiary beds of Bordeaux. V. Daudinii, fig. 225.

VAGINULINA. D'Orb. A genus of microscopic Foraminifera.

VALVATA. Müll.Fam.Peristomata, Lam. Cricostomata, Bl.—Descr.Thin, turbinated; spire short, composed of from three to six rounded whorls; aperture circular; peritreme acute, entire; operculum horny, spiral.—Obs.This genus of small shells resembles Cyclostoma, from which the recent species may be known by the horny texture of the external surface, being fresh-water shells. The fossils of course belong to the fresh-water formations. V. piscinalis, fig. 322. Europe and North America.

VALVES. (Valva, a door, a folding piece.) The two pieces composing a bivalve shell, which close upon each other, turning upon a hinge consisting of a ligament, cartilage, and teeth. SeeBivalve,Multivalve, andUnivalve.

VALVULINA. D'Orb. A genus of microscopic Foraminifera.

VARIX. (A swelling vein.) A varix is formed on the outer surface of a spiral shell, by the thickened, reflected edge of a former aperture, after fresh deposits of testaceous matter have increased the size by adding to the growth of the shell beyond it. In this manner there are frequently many varices, or edges of former apertures, in various parts of the spire and the body whorl. They are sometimes placed at regular distances from each other, as in Harpa, fig. 419; sometimescontinuous, as in Ranella, fig. 394; sometimesdiscontinuous, as in Triton, fig. 398; sometimesramose, as in Murex, fig. 395; sometimessimple, as in Scalaria, fig. 351; sometimesspinose, as in Murex spinosus. The termvarixhas also been applied to any swelling ridge, such as that on the lower part of the columella of Ancillaria, fig. 456.

VELATES. Montf.Neritinaperversa, Auct. Fig. 326.

VELLETIA. Gray? A genus described as differing fromAncylusin being dextral.Velletialacustris,Ancyluslacustris, Auct. fig. Sowerby Gen. fig. 2.

VELUTINA. Auct.Fam.Macrostomata, Lam.—Descr.Sub-globose, covered with a velvety epidermis; spire short, composed of two rapidly enlarged ventricose whorls; aperture large, sub-ovate; peritreme thin, entire, separated from the last whorl; columella tortuous, thin.—Obs.This shell does not resemble any other genus in the family. Fig. 337. Northern Seas.

VENERICARDIA. Lam. A genus composed of the shorter species of Cardita.

VENERIRUPIS. Lam. (FromVenusandrupis, a rock.) The oblong species of Venus Auct. which live in cavities of rocks and stones. This genus is united by Sowerby with some other species of Venus under the name Pullastra. V. Vulgaris, fig. 97.

VENTRAL. (Venter, the belly.) The margin of a bivalve shell opposite the hinge. The under valve in Brachiopodous bivalves is the ventral valve. The ventral surface of an univalve spiral shell is that which faces the observer when the aperture is placed towards him. The ventral part of the whorls of symmetrical convolute shells, is the inner part, that which is nearest to the spire.

VENTRAL SIPHON. In symmetrical convolute univalves, is one placed near the inner edge of the whorls.

VENTRICOSE. (Ventricosus.) Swelled, rounded out, (bombé Fr.) as Harpa ventricosa, fig. 419.

VENUS. Auct. (Goddess of Beauty.)Fam.Marine Conchacea, Lam. Conchacea, Bl.—Descr.Equivalve, inequilateral, sub-globose, sub-ovate, transverse, externally rugose, striated, ribbed, cancellated or smooth; margins entire, simple, close; hinge with three more or less distinct cardinal teeth, diverging from the umbones in each valve; muscular impressions two, lateral, distant; palleal impressions sinuated posteriorly; ligament external.—Obs.This extensive genus, including some bivalves of splendour and beauty, justifying the name given to it, may be known from Cytherea by the absence of a lateral tooth, which is found near the cardinal teeth in the latter. Artemis is distinguished not only by its beautiful form, but by the deep angular sinus in the palleal impression. Fig. 119, 119a. Found mostly in temperate and tropical climates.

VERMETUS. Adanson.Fam.Scalariana, Lam. Cricostomata, Bl.—Descr.Spiral at the apex, irregularly twisted towards the aperture; aperture round, small.—Obs.This shell resembles the Serpulæ in general appearance, although it is regularly spiral near the apex. The animal is known to be a true mollusc, rather nearly allied to that of the genus Dentalium, which is also placed wrongly in the Lamarckian system. Vermetus Lumbricalis, fig. 345. Coast of Africa.

VERMICULAR. (Vermicularis.) Worm-shaped, tubular, serpentine.Ex.Vermilia triquetra, fig. 7.

VERMICULARIA. Lam.Vermetus, Adanson; afterwardsVermetus, Lam.

VERMILIA. Lam. A genus composed of species of Serpula, which are attached by the whole length of the shell, no part being free. Vermilia triquetra, fig. 7.

VERTEBRALINA. D'Orb. A genus of microscopic Foraminifera.

VERTEX. Apex.

VERTIGO. Müll.Fam.Colimacea, Lam.—Descr.Cylindrically fusiform, sinistral, hyaline; aperture marginated, sinuated, denticulated on the inner edge; peristome sub-reflected.—Obs.This genus of minute land shells, resembles Pupa, but is a reversed, hyaline shell. Vertigo pusilla, fig. 293. Europe.

VERRUCA. Schum.Clitia, Leach.

VESICA. Sw. A sub-genus of Bulinus, Sw. p. 360.

VEXILLA. Sw. A genus of "Nassinæ," Sw. thus described: "General shape ofPurpura, the inner lip flattened and depressed; the outer, when adult, thickened, inflected and toothed; aperture wide; pictaSw.Chem. pl. 157, f. 1504-5." Sw. Malac. p. 300.

VIRGULINA. D'Orb. A genus of microscopic Foraminifera.

VITRELLA. Sw. A sub-genus of "Bullinæ," Sw. Lardn. Cyclop. Malac. p. 360.

VITRINA. Drap. (Vitreus, glassy.)Fam.Limacinea, Lam. and Bl.—Descr.Ovate, thin, glassy, fragile; spire short; last whorl large; aperture wide, transverse; peritreme simple; columella spiral, linear.—Obs.This genus of land-shells is not known in a fossil state. The recent species are found among moss and grass, in shady situations. De Ferussac has divided this genus into Helicolimax, fig. 263, and Helixarion, fig. 262.

VITULARIA. Sw. A genus of "Muricinæ," Sw. thus described: "General habit ofMuricidea, but the inner lip is depressed and flattened as in thePurpurinæ; varices simple, nearly obsolete. Tuberculata, Sw. En. M. 419. fig. 1. (Murex vitulinus, Auct.)" Sw. p. 297.

VIVIPARA. A generic name given by Montfort, and retained by some authors forPaludina, Lam. on account of the animals beingviviparous, i. e. the young being perfectly formed before they leave the ovaries.

VIVIPAROUS. SeeVivipara.

VOLUTA. Auct. (Volvo, to revolve.)Fam.Columellaria, Lam. Angyostomata, Bl.—Descr.Sub-ovate, rather angulated, thick, generally tuberculated, smooth; spire short, conical, with a mammillated apex; aperture generally angulated, large, terminating anteriorly in a deep notch; columella smooth, with several plaits, of which the lowest is the largest; outer lip thickened within.—Obs.The genus Voluta, as left by Linnæus, is only characterized by the folds on the columella, and includes many shells which, although they agree in this respect with the genus, are yet quite opposite to each other in all other characters. Thus the Auriculæ, which are land shells, and have the aperture entire, are mixed up with others which are marine, and have a canal, as Turbinellæ, and the Fasciolariæ, and others which have merely a notch, as the true Volutes. This genus, as it is circumscribed at present, includes a great number of beautiful shells, most of which are rich in colouring.CymbaandMelohave been separated by Mr. Broderip from the genusVolutaof Lamarck, for reasons stated in their respective descriptions. Fig. 443.

VOLVARIA. Lam. (Volva, a shuttle.)Fam.Columellaria, Lam.—Descr.Cylindrical, convolute, spirally striated; spire very short, nearly hidden; aperture narrow, as long as the whole shell; columella with three oblique plaits; outer lip dentated.—Obs.The Volvaria are only known in a fossil state, and resemble some species of Bulla in general form, but are distinguished by the plaits on the columella. Fig. 439, V. concinna.

VOLUTELLA. Sw. (A little volute.) A genus composed of those species ofMarginella, Auct. which have the spire concealed, and the aperture smooth within. Fig. 438,Persiculaof Schumacher.

VOLUTILITHES. Sw. (Voluta, andλιθος,lithos, a stone.) A genus composed of some fossil species of Voluta, which have the plaits on the pillar generally numerous, indistinct, and sometimes wanting altogether, with a pointed spire. Fig. 436, V. spinosa.

VOLUTION. SeeWhorl.

VORTICIALIS. Lam. A genus of microscopic Foraminifera.

VULSELLA. Lam. (A little tongue.)Fam.Ostracea, Lau. Margaritacea, Bl.—Descr.Equivalve, irregular, longitudinal, compressed, oblong; umbones separated by a slight area in both valves; hinge with a large pit in the centre, containing the cartilage, the ligament being spread over the areas; muscular impressions, one on each valve, sub-central, oblong.—Obs.This genus differs from Ostræa in the equality of the valves, and in having a hollow pit in the hinge for the cartilage. Vulsella lingulata, fig. 185.

WATERING-POT. Aspergillum, fig. 44, commonly so called on account of the resemblance of its perforated termination to that of the spout of a watering-pot.

WENTLE TRAP. Scalaria pretiosa, commonly so called.

WHORL. A complete turn or revolution round the imaginary axis of a spiral shell. The last whorl is called thebody-whorl. The whorls are described asnon-contiguous, when they do not touch each other;continuous, in the opposite case.Depressedwhen they are flat. They areangulated,heeled, or coronated;distinct, or indistinct. They are sometimes, as in Cypræa, hidden by the last whorl.

XYLOPHAGA. Sow. (ξυλον,zylon, wood;φαγω,phago, to eat.)Fam.Tubiscolæ, Lam.—Descr.Equivalve, globose, closed at the back; with a large, angular hiatus in front; hinge with a small curved tooth advancing from beneath the umbones in each valve.—Obs.This shell, which is found in a cylindrical cavity, eaten in wood by the animal, resembles Teredo, but has not the shelly tube, nor the posterior hiatus. X. dorsalis, fig. 50, 51.

XYLOTRYA. Leach.Xylophaga, Sow.

ZONITES. Montf. A genus formed of Helix Algira, and other similar species with depressed spires and large umbilici; included in the sub-genus Helicella. Fig. 279.

ZUA. Leach. A genus described as differing from Bulinus in having a polished epidermis, and a thickened, not reflected lip. Zua lubrica, B. lubricus, Auct.

ZURAMA. Leach. A sub-genus of Helix. H. pulchella, Auct. Gray's Turton, p. 41.

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