HALIOTIS.VERMETUS.SCALARIA.
"With the genusHaliòtisyou are already acquainted. The animal appears to be veryelegantly formed, if the plate I have seen of it be correct.
"There is a number of fine specimens in the British Museum.
"The familyPlicaceacontains only,
"All the species have plaits, or folds, on the columella. The shells are marine and foreign in both genera. (Plate 9.)
"Our next family,Scalariana, contains the genera
"The single species of the first genus,Vermetus lumbricalis, inhabits the sea near to Senegal. The shell is tubular, thin, twisted spirally; it is fixed on marine substances by the end of its thin, pointed spire. The shells are usually found in groups.
"The genusScalariais one of the most elegant among univalve shells. The singularity of the numerous ribs renders the shells easily known from all other genera of turretedMollusca.The aperture is nearly round, the whorls gibbous, or inflated with carinated ribs: the colour is usually pink or white. It is very costly. (Plate 9.) These shells are brought from the East Indies.
"The fossil species are very elegant: they are found in the strata above the chalk.
"Two other species are common,S. communisandS. lamellosa. The first is a British species, and is called thefalse Wentletrap.
DELPHINULA.SOLARIUM.
"The shells of the genusDelphinulaare solid, thick, somewhat discoid, often armed with spines, without any apparent columella. The recent species inhabit the Indian Ocean. There are several fossil species ofDelphinula.
"TheTurbinaceafamily contains many genera, with which you will soon become familiar. I believe you are already acquainted with this shell, which, from the time it was first known to collectors, has always been celebrated for beauty. It is now calledSolarium perspectivum. (Plate 9.) The large, spiral, crenated umbilicus is its great peculiarity. The French call the shellCadran,dial. In its natural state the shell is covered with an epidermis. There are a few fossil species, one in the oölite of our own country. The English name isstaircase trochus.
ROTELLA.TROCHUS.TURBO.
"The genera ofTurbinaceaare,
"The genusRotellacontains small, flattened, wheel-shaped shells, common in most collections. They are smooth and polished.
"Trochusis still a large genus.Trochus marmoràtusis a fine species from the Indian Ocean. There are several handsome species on our own shores.T. magusis one of them; it has a large, deep umbilicus, or perforation; the spire is flattened; the whorls are crowned with tubercles. TheTrochiof tropical climates are thinner than those of northern latitudes.
"When any of these shells are placed upon theirbase, their axis is always inclined: of course they never stand perfectly upright.
"There are several fossil species.
"The genusMonodontaholds a middle place betweenTrochusandTurbo, differing from the former in the aperture, and from the latter in the columella, which is arched and truncated at the base. They are all marine shells.
LITORINA.TURBO.PHASIANELLA.
"From the well-known genusTurbo, a new one has been formed, calledLitorina, which includes all the shells of our own coasts that formerly ranked underTurbo. Consequently we find the periwincle has changed its generic name, and fromTurboit is altered intoLitorina.T. muricatais now of the same new genus,Litorina muricata. (Plate 7.)
"Turbo picais a large pearly shell known as the magpie. The golden-mouthedTurbois very brilliant; the aperture appears as if gilded, so fine is the yellow tint. It comes from the Molucca Isles.Turbo smaragdus, from New Zealand, is a rare and beautiful species of a bright green colour.
"Phasianellais a beautiful genus of shells, formerly very costly. A small but elegant species is found on our own shores,P. pullus,Turbo pullusof some authors. The colour is pink.
"Phasianella bulimoides, from New Holland, is the largest of the species, and once a very rare shell.
"The termTurritellawill give you an idea of the form of our last genus in the familyTurbinacea. The shells are likelittle towers, with a circular aperture. The older conchologists gave the name ofscrewto all turreted shells, without attending to the form of the aperture. Hence we find screws amongTurbo,Buccinum, andStrombus(spindle).
TURRITELLA.
"Turritella duplicatais a heavy shell, often more than four inches long. It is sulcated and carinated; the colour is yellow-white.T. bicingulatais white, marbled with yellow; the whorls are girded with two ridges. There are several fossil species of this genus in London clay."
"I think," said Lucy, "that three or four genera have been taken out ofTurbo—Scalaria,Delphinula,Litoralia, andTurritella, and thatLitoraliais not Lamarck's genus."
"You are correct," replied her father, "and indeed so many alterations are continually taking place in the generic names of shells, that I cannot enter into all the niceties of modern conchologists. However, the generic name of a shell, according to Linnæus or Lamarck, is usually given, therefore I hope you will not be greatly at a loss upon meeting with some apparently unknown genus."
CHAPTER XI.
RANELLA.VOLUTA.OVULA.
"What is Charles drawing from his pocket with a look of so much importance," said Mr. Elliot, the next time they met.
"There isRanella crumena, thorny-frog;Ovula gibbosa, the shuttle; andVoluta musica, the music-shell," said Charles.
"Oh, who gave you those nice shells?" asked Lucy, "and how do you know the names?"
"Let my father say if I am correct, first," replied Charles.
"Perfectly," answered his father; "but I fancy that I can guess how you obtained your information. You have been buying these specimens, and had the names from the shell-vender. I hope your purchase did not cost much, for they are not rare shells?"
"No; I should not choose to spend a large sum, even from my purse, until I am a better judge of the value of shells. But as our collection is but small, I thought that Lucy would be glad to see an addition to the stock."
CANALIFERA,CERITHIUM.
"Thank you, brother," said Lucy, "younever forget me in your purchases or your pleasures."
"Let us return to our subject," said Mr. Elliot, "and notice the families of the next section, which are all carnivorous, living on animal substances. They have a projecting syphon, which conveys the water to them: they are all marine. The syphon passes through the base of the aperture, either into a canal, or channel, or a narrow, recurved margin. The mouth is furnished with a trunk.
"Canaliferacontains in the first section,
FOSSIL CERITHIUM.TURBINELLA.
"The naturalist Bruguieres established the fine genusCerithium, mixed by Linnæus among those ofMurex,Strombus, andTrochus. These shells are always turreted, having a short canal at the base; the aperture oblong, oblique, with a gutter turned backwards. (SeeFrontispiece.) Many are girded with zones, that are granulated, or beset with little tubercles. It isremarkable thatCerithium giganteum, a species more than a foot in length, is found fossil in France, and as a living species in the seas of New Holland.C. telescopiumis a fine shell from the East Indies.C. vertagusis smooth, tawny-white, with a recurved canal. It comes from the Moluccas. Many species occur fossil in London clay and in plastic clay: the Woolwich pits afford specimens, and also ofTurritella.
"Pleurotoma, formerly united withMurex, is distinguished by the singularnotchin the right-margin of the shell. One species, the Tower of Babel, is well-known, and another is common under the name ofMurex javanus. The fossil species are numerous.
"Turbinellais taken fromMurexandVoluta: some species are thick, heavy shells, from the Indian seas.
"Cancellariais an elegant genus: the shells are varicose, reticulated, or cancellated; the columella has folds upon it, varying in number, the right-margin sulcated within. There are several fossil species, which are considered very beautiful.
"Fasciolaria trapezium, the Persian robe, is a fine shell from the Indian seas, very common in collections.
FUSUS.PYRULA.RANELLA.
"The genusFususconsists of spindle-shaped shells, of whichFusus colus, the distaff, willgive an idea. They are covered with an epidermis which conceals, in some species, the fine colours beneath.
"Fusus despectus(Murexof Linnæus) is the largest of the British turbinated shells, and very common: it is the large whelk.
"Fusus contrarius, the reverse whelk, is found fossil in the Essex crag.
"Among the shells of thePyrulagenus we findP. ficus, the fig, placed by Linnæus among theBullarace.P. spirillusis a pretty species, with a long canal and a flattened spire, having a tubercle at its termination.
"Second section ofCanalifera: shells with a varix on the right-margin.
"Struthiolaria, ostrich-foot, is a remarkable shell from New Zealand.
"Ranella, thorny-frog, is frequent in collections: there are several species:R. crumenais easily obtained—you must purchase a specimen.
MUREX.TRITON.
"Notwithstanding the great reductions of theMurexgenus, it is still large, and contains veryfine species. The shells havethree or morevarices upon each whorl; those inRanellabuttwo; whileStruthiolariahas a varix only on the right-margin. The species are numerous, and common in collections.M. saxatilisis white, and zoned with rose-colour or purple. The foliations, or branches, are erect. The Rose-bush is pretty; and the wagtail,M. motacilla, will, doubtless, be a favourite with you, as well as the scoop,M. haustellum.
"Notwithstanding the resemblance of the genusTritonto those ofMurexandRanella, there are permanent differences which make them distinguishable at first sight. I have already noticed the varices of the preceding genera; inTritonthey never form longitudinal ranges, but are alternate, few, and nearly solitary on each whorl of the spire; these varices are generally smooth and without spines.[C]Triton variegatum, the marine trumpet, is a large, handsome species, from the Asiatic seas.T. lampasandT. lotoriumare common.Triton anusis very remarkable.
[C]Lamarck.
[C]Lamarck.
"In the next family,Alata, we must notice a remarkable fact: the shells, while they are young, assume a different form to those more advanced in growth.
ROSTELLARIA.PTEROCERA.STROMBUS.
"The genera are three—
"In the first genus the shells are terminated below by a canal, or pointed beak; the right-margin entire, or toothed, more or less dilated with age, and having a sinus contiguous to the canal. There is a specimen from our own coast,Rostellaria pes-pelicani, the pelican's-foot: it wasStrombusof Linnæus. (Plate 7.) There are many of this species found in a fossil state.
"ThePteroceragenus is easily known by the digitated, or fingered, appearance of the right-margin. The greater part of the species become very large. Here we find the scorpion, with seven digitations, from India; the spider, with the same number, a large and fine shell, also from India.
"Strombushas a short canal, the right-margin dilated with age into a simple wing, having, at the lower part, a sinus, separated from the canal at the base of the shell.
"All the species are natives of hot climates; some attain a very large size, such asS. gigas, so frequently seen in shops, and as ornaments in a room.S. gibbèrulusis a pretty little shell; the white, gibbous whorls render it remarkable;the interior of the lip is pink.S. lineàtushas dark lines round the shell.S. vittàtushas a very long spire; the colour is tawny, girded with white: you may easily meet with this species.
CASSIDARIA.CASSIS.
"The familyPurpuriferais composed of genera taken chiefly from the large Linnæan genusBuccinum.
"It is thus divided:
"First, the genera with the canal ascending, or turned towards the back of the shell—
"Cassidariais not a very common genus; but the helmets,Cassis, are both numerous and plentiful in most collections. The straight aperture slightly reminds you of aCypræaperhaps, but the short canal, abruptly turned back, is a clear distinction; the right-margin generally toothed; the columella folded, or wrinkled, transversely.
"C. cornuta,C. flummea,C. arèolaandvibex, are all well-known species,C. cornutahas large tubercles like horns round the tip of the shell.C. arèolais marked with chequers.C. rufus, from the Moluccas, is a fine shell, with a deeply coloured red aperture.
"In the next division the canal is oblique, and directed backwards.
NASSA.RICINULA.PURPURA.
"To these genera another has been added, calledNassa, of whichBuccinum arculariawill furnish an example. The columella has a callosity very evident in the speciesPullusandThersites.
"Ricinula horridahas a ringent aperture of a fine violet colour; the shell is thick, and covered with large black tubercles. The genus takes its name from a resemblance to the seeds ofRicinus.
"Purpurais a large genus: in certain of the species the colouring-matter exists of which the ancients formed their famous purple dye. It is the last genus that offers any appearance of a canal at the base of the aperture.
"P. patula, the scoop, from the Atlantic and Mediterranean, has the aperture remarkably dilated, the margin sulcated.
"P. lapillusis a common British shell amongthe chalk-cliffs of the coast; the colour varies, sometimes white, at others yellowish.
MONOCEROS.CONCHOLEPAS.HARPA.
"I shall describe a species of the singular genusMonoceros, by which you will scarcely fail to recognise it.
"The columella is flattened likePurpura patula; just within the outer lip is a row of small teeth; but the principal peculiarity is a process, or horn, near the outer part of the lower lip, and close to the canal, from which the genus derives its nameMonoceros,one-horn. It is brought from the seas of America.
"Concholepas Peruviana, the only species, is also a remarkable shell. The aperture is very large, almost equal to the shell itself; the spire is near the edge; the outside is marked with ribs, or costæ; there are two short teeth on the right-margin. This shell was placed among thePatella.
"The beautiful genusHarpa, harp-shell, is remarkable for its elevated ridges on the back of the shell, its large aperture, and its fine colouring. They are East Indian shells.H. ventricosais a common species.H. nobilisis very fine, and alsoH. costata.
"Equally well-known are the Tuns,Dolium, by their globose form, the right-margin toothed, and a canal below. They reach a large size, and are light shells in proportion to their bulk.Dolium galeumis sometimes the size of the human head.D. perdixis a choice species.
DOLIUM.BUCCINUM.EBURNA.
"Buccinumcontains some British species, asB. reticulatum, (Plate 7,)B. anglicanum,B. undatum, which is very common. In connexion with this species I wish you to know that a marine substance, called by sailorssea-wash balls, by others sea-sponge, and extremely common on all our sea-coasts, is the egg-cases of theBuccinum undatum. The mass is remarkably light, and composed of numerous little cells, each of which has an opening. The colour varies from yellow to white."
"I know them well," exclaimed Lucy, "how often I have asked the name of those nests, but never could I obtain a reply worth having! And now, father, give me leave to interrupt you a few minutes. What are those black, stiff, marine substances, with a horn-like projection at each of the four corners; they are all hollow, and open at each end, I think, and usually inflated?"
"The egg-cases of the scate."
"Thank you, father, I will examine them again carefully when I am at the sea-side."
"The genusEburna," continued Mr. Elliot, "is remarkable from the smoothness of the shells.E. spirata, the Joppa whelk, has the whorls deeply channelled. (See theFrontispiece.)The columella is umbilicated, and has a canal beneath it.
TEREBRA.COLUMBELLA.
"TheTerebragenus is turreted; very acute at the apex. (Plate 9.)
"The familyCollumellariais next in order. Thecanalnow disappears at the base of the shell, but there is a slope and folds on the columella. We have reached the large genusVolutaof Linnæus, greatly reduced by withdrawing the following genera:
"The shells ofColumbellaare of small size; two species are very common in collections.C. mercatoriais a little shell striated transversely; the outer lip is thickened in the middle, and toothed; the columella is plaited: the animal is furnished with an operculum.
"Columbella nitidais another pretty species, smooth and shining: you may perceive the generic marks if you look closely—two small folds on the pillar-lip, and the swelling, toothed,outer margin. They are all West Indian marine shells.
MITRA.CYMBA.MELO.
"Mitrais a large genus, and it is believed that there are three times as many species yet undescribed. The mitres are natives of warm climates, and few are common. The pillar-lip ofMitrais parallel, with transverse folds; the base has a slope, but no canal; the margin of the columella is thin and rolled back.M. episcopalis, the bishop, is white with red spots; the columella-folds are four. (Plate 9.)M. papalis, the pope's-mitre, has five; the upper whorls are broken into a kind of crown.
"InCymba, the gondola, the spire ends in a tubercle, and scarcely appears; the aperture is wide: they are very pretty shells.
"Melo, the melon, from the Indian Ocean, is a very fine genus; here the spire is evident.
"Voluta musicawill serve as an example of the genus. The animal is carnivorous.
"Marginellais an oblong, smooth, and polished shell; its peculiar character is the thickened outer lip; it is a neat, small species, prettily coloured.
"Volvariais a cylindrical shell, convolute, the spire nearly hidden; the aperture straight, as long as the shell. There is a fossil species found in London clay.V. monilisis sometimes strung for necklaces. It comes from Senegal.
OVULA.
"The last family of the orderTrachelipodaisConvoluta, which contains many very fine genera.
"They are the following:
"The general characters of this family are the following:
"Shell without a canal, the base of the aperture sloping, or effuse, the spire compressed, the last volution almost covering the rest.
"Ovula, you will recollect, was formerly confounded with theBullagenus: the form is egg-shaped, the outer lip toothed in one division, smooth in the other; the shells are white and polished, particularlyO. oviformis, the poached-egg, from the Moluccas.
"O. volva, the weaver's-shuttle, is a rare and highly-valued species. It is nearly globular in the middle, and is terminated at each extremity by a long beak: it comes from the West Indies.O. gibbosais a common species; the shape is oblong, with a ridge in the centre.
CYPRÆA.TRIVIA.
"You can be at no loss on seeing the shells ofCypræa, a large and beautiful genus, which remained unchanged for a long time. Lately, we find a few of the small species are become a new genus,Trivia.
"The character of theCypræais a longitudinal aperture, toothed, in the adult state, on each side. The spire is scarcely to be seen.
"While the shells are young they have the appearance of aVolutaor a cone; the aperture spreads more, and is without teeth.
"The individuals of each species pass through three different states:
"In the first, the form is very imperfect; it is like a thin cone, and shows no character of the genus; hence young students are perplexed if they chance to have a young cowry in their collection.
"In the second state, the shell is still thin, with aprojectingspire; but attains its proper form.
"In the third, or adult state, the shell is thick, the colours are perfected, and the spire is very nearly concealed.
"When the animal becomes too large for its habitation, it has the power of leaving it, and forming a new one.[D]
[D]Lamarck.
[D]Lamarck.
CYPRÆA.
"The inhabitant of theCypræashells has two tentacula of a conic form, and finely pointed; the foot discous, and sometimes tongue-shaped. The mantle is two-lobed, with wing-like margins, capable of being turned back over the shell: this mantle preserves the shell from injury when the animal issues forth in search of food. The genus abounds both in the old and new world; but the larger kind chiefly in warm climates. They live on the coast, and are generally found under stones or rolled coral. A very few species are natives of the European seas.
"The tiger-cowry is before you; a large and very common species in collections; it also frequently adorns the mantel-piece. There is a remarkable line extending along the back of the shell; at this part the edges of themantle, that I have before noticed, meet: this line is conspicuous in many species.
"C. aurorais a costly shell from Otaheite and New Zealand; the colour orange, with the base and extremities white. It is large, and has been sold for 60l.when a specimen has been obtained without any perforation. The shell is worn by the New Zealand chiefs as a badge of honour.
"C. exanthemachanges its appearance greatly as it advances in growth. While young, three bands extend over the back, which in its adult state disappear, and the fawn-coloured ground isspotted over with numerous white circular marks.
CYPRÆA.
"C. mauritania, the moor, is a fine species, with very black sides, and tawny-yellow back with spots. It is a native of Java.
"C. caput-serpentis, the serpent's-head, has dark sides, with white fauces: the back is covered with net-work colouring: the fauces, you must remember, are the narrow entrances at each end of the shell.
"C. Isabella, the orange-tip, with pale flesh-colour back, and the fauces orange-colour.
"C. Arabicais a common species in collections.
"C. mappais varied with deep brown or yellow lines and spots: the dorsal line is laciniated.
"C. talpa, the mole, has the back fawn-colour, with three zones of pale yellow; the base and sides sometimes nearly black. It comes from Madagascar.
"C. vitellus, the fallow-deer, is fawn-colour, covered with small white spots: from the Indian Ocean.
"The wasp,C. asellus, is white, with three brown bands.
"C. helvola, the star-cowry, has the sides dark orange; the fawn-coloured back studded with small spots. It comes from the Maldives.
"C. moneta, the money-cowry, is generally white, sometimes yellow.
TÆREBELLUM.OLIVA.TRIVIA.
"C. annulus, the ring-cowry, has a yellow mark round the top of the shell. The fowl-cowry,C. moneta, is used for money by the natives of Siam and Bengal.
"C. pediculusis changed toTrivia, a new sub-genus fromCypræa. We find the following characters:—form of the columella internally concave, ribbed; shell sub-globular, cross-ribbed.T. carnea, flesh-coloured shell; thin, pure rose-coloured, with very thin, distant ribs; lips whitish: it has sometimes an indistinct dorsal groove.
"Trivia Europæa(Cypræaof authors) is a globose shell, ash or flesh-coloured, with three black dots and a whitish dorsal streak; ribs close, rather thick, and whitish; base white; outer lip wide. The variety has the back without spots.T. pediculushas six square dorsal spots; the colour of the shell pale red; ribs rather thick-covered; dorsal line narrow; base reddish. Only one species,C. Europæa(orTrivia) is a native of our shores.
"There are several fossil species ofCypræa.
"We now pass on to a genus in which there is but one recent species,Terebellum subulatum,Bullaof Linnæus. (SeeFrontispiece.) A fossilTerebellumis found in London clay.
ANCILLA.CONUS.
"TheOlivagenus contains smooth, shining shells, common, and therefore little valued; nevertheless they are beautiful, and of various colours.
"The columella is obliquely striated; the aperture longitudinal and straight. The olives were placed by Linnæus among theVolutæ, on account of the striæ on the columella, without regard to the peculiarity of thecanal, by which the olives are known from all other shells. This canal separates thevolutionsofOliva. Many species are prettily marked by nature, others are rendered handsome by polishing.O. subulatais small, and pointed like a mitre. The common olive is white, with brown, waved lines.O. irrisansis ornamented with yellow zigzag lines: it has two brown zones.O. oriza, the little rice-olive, is white.
"I should have noticed the small genusAncilla, formerlyAncillaria, which is very near both toTerebellumandOliva. The columella has a varix at the base, which distinguishes it fromTerebellum, and it wants the canal which separates the volutions ofOliva.
"There are several fossil species.
"The concluding genus of the third order is very large, and contains rare and costly shells. This isConus, scarcely to be mistaken for any other genus exceptVoluta, and that only at a first glance.
CONUS.
"The species are covered with an epidermis, sometimes very thick; the spire has various degrees of elevation, sometimes almost flat; the operculum very small and horny. They are natives of southern and tropical seas: the animal is carnivorous: found in sandy mud, at various depths of the ocean. The species are very numerous—Lamarck makes 181 recent. Some new species have lately been discovered. Many of the cones are very beautiful, both in shape and colour, and the genus has been always in estimation among collectors. Thegloria-maris,cedonulli,ammiralis, and some others, have been sold at very high prices, and some of the finest of these are now in England.
"Lamarck makes two divisions: in the first is comprehended the species with coronated spires; the second those with simple spires; the latter division contains far the greater number.
"Fossil cones occur, in London clay and crag, in England.
"No recent species are found upon our own coasts.
"Conus Hebræus, the Hebrew-cone, is easily known: (Plate 6:) it has a white ground, and square black markings.
"Conus virgois white, with a purple base.
CONUS.
"C. marmoreusis a fine shell. Numerous species are within reach of your purses, and I do not doubt that you will soon acquire a good collectionat a moderate price. You, Charles, will find more pleasure in a cone than in a top; and Lucy, who never found much pleasure in toys except in taking them to pieces, has always a ready sixpence either for a poor neighbour in distress, or for some harmless pleasure.
"We have yet two more orders ofMolluscato notice, theCephalopodaand theHeteropoda.
"At our next lesson I shall mention the genera that are most likely to come under your observation, either fossil or recent."
CHAPTER XII.
ARGONAUTA.NAUTILUS.
"So many families of the fourth order,Cephalopoda, are found only in a fossil state, and which you will not easily meet with, that I shall not consider it needful to give you the whole catalogue," observed Mr. Elliot to his young pupils at the beginning of the next lesson.
"But we are exceedingly interested about fossils," replied Charles; "pray do not pass any species that we may be likely to find."
"And I," said Lucy, "have much wished to ask whether thesnake-stoneever was a shell? it is something like aPlanorbis, but heavy and imperfect."
"I will answer your question presently," said her father. "Tell me what genera remain to be noticed among the univalves of Linnæus?"
"ArgonautaandNautilus," was the ready reply.
"The animals inhabiting these shells areCephalopoda. The word indicates the position of the feet, or more properlyarmsof the animal, which are ranged round the head like a crown.The body is thick and fleshy, contained in a kind of bag, whence the head issues, surrounded by these arms, which vary in different genera.
CUTTLE-FISH.BELEMNITE.SPIRULA.
"The commoncuttle-fish, a native of our seas, will give you an idea of a cephalopode.
"In the first family a fossil-shell occurs that is very frequently met with.
"Family,Orthocerata; genus,Belemnite, thunder-stone, or arrow-head. These fossil-shells occur abundantly in the chalk formations. Many superstitious notions have been attached to this extinct marine animal: of these you will find an account in the 'Penny Cyclopædia.'
"In the familyLituolitawe meet with the delicate and remarkable little shellSpirula Peronii, distinct fromNautilusby the separation of the volutions: it is nearly covered by the body of the animal. The colour is white; the texture thin and brittle: it has a lateral syphon, the orifice of which is very clearly to be seen as each compartment is taken off. There is but one species; it is found in the Southern Ocean and the Moluccas. The shells are seen floating on the surface of the water when the animal is dead, and are sometimes carried to the shore. (Plate 9.)
AMMONITE.NAUTILUS.
"Another family of this order,Nautilacea, contains, among many other genera, the celebratedNautilus. This genus, you are already informed, is distinguished fromArgonautabyits shells being many-chambered. Two or three fossil species have been found in London clay.
"Among the various fossil-shells abounding in different strata, not known in a recent state, the one most remarkable and frequently occurring is the Ammonite,Cornu Ammònis, so called from the resemblance it bears to the convoluted horns of Jupiter Ammon, in mythological history. This is yoursnake-stone, Lucy, a local name, which you had better change for Ammonite. Various legends are connected with this fossil, of which you may obtain information by consulting the before-mentioned publication.
"As you are desirous of studying geology, a knowledge of the Ammonites is very requisite, since whole sections of the genus are characteristic of certain strata.
"They are nearly allied to theNautilus. The species are very numerous; one hundred and twenty according to some authors—two hundred and seventy species are enumerated by others. They occur in Europe, Asia, and America: they have been found in the chalk with a diameter of three feet.
"In the second division of this order the genusArgonautaoccurs: the shell has been already described, and retains its original name. (Plate 6.)