Genus AMPHISIA Sterki '78.

Epiclintes radiosaQuenn. Fig. 50.

Synonym:Metra radiosaQuenn.

The body is elongate, slightly narrowed anteriorly, and drawn out posteriorly into a long, retractile, tail-like portion. Five large cirri extend outward from the anterior extremity. The caudal portion may be extended to a distance equal to twice the length of the body or contracted to half the length. The peculiar nervousness of this form made it extremely difficult to study, and the oral region was imperfectly made out. The anterior cirri appear to line the upper left border of the peristome, which is marked by a row of large cilia. The peristome begins upon the right side of the anterior end and passes backward and to the left, narrowing at this point. The mouth is very small and difficult to see. It is apt to stay in one locality under zooglœa, switching back and forth with great vivacity, or hanging on by the posterior cilia while the anterior end stretches out in the surrounding medium. Nucleus and contractile vacuole were not observed. Length 45µ.

(Sterki '78; Kent '81; Bütschli '88.)

The body is plastic and soft, colorless or slightly tinged with yellow or red. In form it is oval or elongate, the posterior end is rounded and slightly reduced in diameter, but does not form a distinct tail. The anterior end is also rounded and similarly reduced in width. There are two rows of marginal cirri (Randcirren), which may be placed some distance from the edge, and two or three rows of ventral cirri between them. There are from 3 to 5 frontal cirri of larger size than those of the ventral rows, and from 5 to 10 anal cirri. (The genusHolostichais similar in all respects save the presence of frontal cirri.) The macronucleus is double; the contractile vacuole is central and on the left side. The peristome is long and rather narrow and carries an undulating membrane on its right margin. Fresh and salt water.

Amphisia kessleriWrzes. '77. Fig. 51.

Synonyms:Trichoda gibbaMüller;Oxytricha gibbaStein '59;O. velox?Quen. '69;O. kessleriWrzes. '77.

Body elongate, slightly sigmoid and swollen in the center, about 3-1/2 times as long as broad; the rounded anterior end is turned to the left, the similarly rounded posterior end to the right; both ends taper slightly. The peristome is long and narrow, with a distinct adoral zone which appears broken in its course. To the right of this adoral zone is a single line of preoral cilia. On the right border of the peristome is an undulating membrane. The three frontal cirri form a triangle and the five smaller anal cirri form a continuous line with the broken row of ventral cirri. There are two and one-half rows of ventral cirri and the marginal cirri are drawn in until they are ventral in position.

Length 135µ; greatest width 40µ.

Amphisia kessleriFig. 51.—Amphisia kessleri.ENLARGE

This variety differs fromO. kesslerias described by Wrzesniowski in having three frontal cirri instead of four. Another difference is in the structure of the nuclei and in their position. These differences are too minute to warrant a specific name.O. veloxof Quennerstedt is probably the same as0. kessleri, but differs in having three complete rows of ventral cirri.O. veloxhas three frontal cirri in a line, thus differing from the Woods Hole form.

Key to the marine genera of Euplotidæ.Diagnostic characters:Cilia, as well as the frontal, marginal, and ventral cirri, very much reduced; the anal cirri, on the other hand, are always present. The macronucleus is band-form.1.Frontal cirri more than 82Frontal cirri less than 832.Eleven marginal cirri on the left side; 11 frontal cirriGenusCertesiaFour marginal cirri, 2 on each side; 9 to 10 frontal cirriGenus *Euplotes3.Seven frontal, 5 anal, 3 right marginal, and 2 left marginal cirriGenus *DiophrysNo frontal, 5 anal, 3 right, and 2 left marginal cirriGenus *Uronychia* Presence at Woods Hole indicated by asterisk.

(Ehrenberg '31, '38; Stein '59; Cl. & Lach. '58; Quennerstedt '65, '67, '69;Bütschli '88; Kent '81; Gourret & Roeser '88; Möbius '88.)

Small to medium-sized forms. Rigid in form, colorless, or green by chlorophyl. They are quite flat on the ventral surface but decidedly arched dorsally, and the contour is usually oval. The anterior end is broadly rounded to truncate; the posterior end is similarly rounded, or may be somewhat pointed. The mouth is placed centrally or near the left margin, and from it the right edge of the peristome forms a curved line to the left, which bends forward, thus making the greater part of the left edge the peristomial area. In front the peristome bends sharply to the right and extends as far as the right end of the adoral zone. Upon the frontal and median ventral surface are 9 to 10 great cirri (Bauchwimpernof Stein). Posteriorly five great anal cirri stretch out beyond the posterior body margin. In addition to these there are two smaller marginal cirri upon the left body edge, and two similar ones on the hinder part of the body. The dorsal surface is rarely smooth, but usually is marked by longitudinal ridges, and rows of dorsal bristles have been described. The single contractile vacuole lies on the right side in the region of the anal cirri, sometimes just above them, sometimes below. The anus is posterior and on the right side. The characteristic macronucleus is long and band-form, its main portion being usually on the left side with an anterior and a posterior arm toward the right. Movement is rapid swimming, which, however, is frequently broken by creeping periods, during which the animals appear to be examining the foreign body on which they creep.

Fresh and salt water.

Euplotes charonEhr. Fig. 52.

Synonyms:Trichoda charonMüller;Plœsconia charon;P. affinis,subrotunda,radiosa,longiremis, Dujardin '41.

The body is oval, small, and somewhat variable in length. The carapace is strongly marked upon the dorsal side by deep longitudinal grooves, 6 to 8 in number; the grooves may be absent, however. The adoral zone extends to the posterior third of the body, the mouth and œsophagus are directed anteriorly. There are 10 ventral cirri, 7 of which are on or near the frontal border and 3 near the right edge. There are 5 posterior cirri and 4 anal cirri, of much smaller size. The cirri may or may not be fimbriated, the latter condition indicating the approaching disintegration of the body and is abnormal. The macronucleus is long and band-formed or horseshoe shape. The contractile vacuole lies on the right side dorsal to the posterior cirri.

Fresh and salt water. Length 45µ; diameter 25µ.

Euplotes charon, dorsal and ventral aspectsFig. 52.—Euplotes charon,dorsal andventral aspects.ENLARGE

Euplotes harpaStein. Fig. 53.

The body is elongate, oval, somewhat widened anteriorly, and has rounded ends. The frontal margin is three-toothed. Ten ventral cirri. Dorsal surface provided with 8 longitudinal markings. The peristome is long and broad, with considerable variation. The adoral zone consists of powerful membranelles arranged in a continuous curve from the mouth to the extreme right frontal margin. Seven of the 10 ventral cirri are situated at the anterior extremity; the remainder are arranged in a triangle on the right edge. The anal cirri, 5 in number, are long and stiff; the marginal cirri smaller and finer. The nucleus and contractile vacuole are similar to those of the preceding species.

Length 95µ; width 54µ.

(Bütschli '88.)

Medium size, colorless to yellow, rigid in form. The body contour is oval, the anterior end being rounded or slightly reduced, the posterior end usually cut in on the right side. The peristome is broad but less extensive than inEuplotes, and may extend beyond the middle of the body. Its right edge is convex toward the right side, extends forward and does not turn again to the right. The anterior ventral surface has 7 to 8 scattered cirri and just behind the mouth is a transverse row of large anal cirri. In the sharp in-cut of the posterior end are three great angular cirri. Two lateral cirri are placed on the left of the median line between the mouth and the anal cirri, and usually in a slight hollow. The contractile vacuole is on the right side in the vicinity of the anal cirri. The macronucleus is in two parts, each band-form, one anterior, the other posterior in position. Movement is rapid and steady. Salt water.

Diophrys (Styloplotes) appendiculatusStein '59. Fig. 54.

Synonyms:Styloplotes appendiculatusStein '59; Kent '81; Quennerstedt '67, etc.

Diophrys appendiculatusFig. 54.—Diophrys appendiculatus.ENLARGE

The general form resemblesEuplotes. Its outline is oval and regular except at the posterior end on the right side, where there is a considerable indentation. The frontal margin is characterized by a row of powerful membranelles, which become smaller at the peristome and at the mouth they are of characteristically small size. The ventral cirri are 7 in number. Five of them are in one row from the anterior end down the right side nearly to the anal cirri; 1 is on the frontal border between the first two; 1 lies just anterior to the second anal cirrus from the right side. The 5 anal cirri are large and powerful and extend some distance beyond the posterior end of the body. In all specimens observed these cirri curve to the left. Dorsal to the anal cirri and placed deep into the dorsal pit are 3 large, sharply curved cirri, which in most cases are fimbriated, but when the specimens are normal these are pointed and curve abruptly to the right. Two smaller cirri lie to the left of the group of anal cirri. The peristome is well-marked by the adoral zone, and upon its right border there is a row of cilia, and a similar row of cilia runs along the base of the oral membranelle. The macronucleus is double and consists of two elongate cylindrical masses lying parallel with one another. One of these is in the anterior region; the other is posterior. The contractile vacuole lies dorsal to the anal cirri and anterior to the three dorsal cirri. The movement and general activities resemble those ofEuplotes.

Length 50µ; diameter 25µ.

(Stein '59, '67; Quennerstedt '67; Kent '81; Bütschli '88.)

Medium-sized colorless ciliates of usually constant body form. The body is somewhat short and oval in outline. The anterior end is broadly truncate, the posterior end rounded or slightly pointed. The ventral and dorsal surfaces are considerably arched and the latter usually has a number of rows of longitudinal stripes. The open peristome is broad and reaches back to the middle of the ventral surface and beyond. According to Stein, the two edges can approach each other, thus opening and closing the peristomial area. Its right edge forms a greater angle with the front edge than in the genusEuplotes, and the left edge forms a greater angle with the front edge than in that genus. The left edge also appears to cover over the adoral zone slightly. There are no ventral cirri in front, but on the posterior ventral surface are 7 great springing cirri. Five of these are inserted on the right aide in a deep in-sinking, and the other 2 in a similar depression on the left ventral surface. Above the 5 right-side cirri,i.e., dorsal to them, but in the same depression, are 3 angular cirri. A few edge cirri are found to the left of them and another to the right of the 5 cirri. The contractile vacuole is on the left side between the main groups of cirri. The macronucleus is band-form or spherical, and is situated in the middle region of the body. Movement consists in forward swimming with sudden springs.

Salt water.

Uronychia setigera, n. sp. Fig. 55.

This species is very common in the Woods Hole waters. It is small, colorless, and very active. The most characteristic feature is the posterior end with its relatively enormous cirri, which are apparently large enough for an animal four times its size. The form is ovoid, widened posteriorly.

Uronychia setigeraFig. 55.—Uronychia setigera.ENLARGE

The ventral surface is flat and has two excavations in the posterior end. The right hollow is larger and contains 5 great cirri of unequal size, the extreme right one being the largest. The left hollow contains 2 cirri, also of dissimilar size. Dorsal to the 5 right cirri are 3 sickle-formed cirri, which are usually fimbriated. These are pointed and curve regularly to the left. The peristome is wide and open, and a small pocket-like hollow on its left border indicates the region of the mouth. The adoral zone runs into this pocket and the mouth is located in its lower right-hand corner. InU. transfugathe right border is generally described as having a membrane of extreme delicacy. I was unable to see such a membrane in this form, but in its place there are 2 flagella-like cirri extending from the margin of the mouth-opening into the peristome, and these vibrate slowly. I do not believe these could be the moving edge of an undulating membrane, for they are quite distinct. The macronucleus is spherical instead of band-form, and a single micronucleus is closely attached. This is unlike the European speciesU. transfuga, in which the nucleus is elongate. The contractile vacuole lies between the two sets of posterior cirri. There are no marginal folds like those of the European species.

Length 40µ; width 25µ. Common.

(Perty '52; Cl & Lach. '58; Stein '59; Quennerstedt '65, '67, '69;Mereschowsky '79; Kent '81; Bütschli '88.)

Small, colorless, and rigid forms, with nearly circular to oval contour. The left side is usually straight, or at least but slightly convex. The right side is much more convex, and the right margin is considerably thickened. The ventral side is flat, the dorsal surface convex, with from one to several longitudinal ridges which run more or less parallel with the right edge. The peristome is limited to the left edge, where it forms a small depression which may or may not reach the anterior border, but which in no case runs around the anterior margin. The left peristome margin in some cases grows over the peristome depression toward the right, thus making a sort of cover for the peristome. In the posterior region is a deep depression, from which 5 to 12 cirri take their origin. Seven or 8 cirri are placed in the anterior half of the ventral surface and are arranged more or less in rows. The anus is on the right side in the region of the anal cirri (Stein). The contractile vacuole is generally on the right side and similarly located. The macronucleus is a horseshoe-shaped body. Movement rapid, somewhat in circles, and rather uniform.

Fresh and salt water.

Aspidisca hexerisQuennerstedt '67. Fig. 56.

The carapace is elliptical, about 1-1/2 times as long as broad, rounded at the extremities. The left border of the carapace bears a spur-like projection. The ventral cirri are short and thick, and are very characteristic of the species. When moving slowly they look much like nicely-pointed paint brushes, but when the animal is compressed they quickly become fibrillated, and then look like extremely old and worn brushes. These cirri are placed in depressions in the ventral surface and each one appears to come from a specific shoulder. At the posterior end an oblique hollow bears 6 unequal cirri placed side by side. The extreme right cirrus is the largest, and they become progressively smaller to the opposite end. Dorsal to these lies the contractile vacuole. The peristome is in the posterior half of the body and an undulating membrane extends from it into the œsophagus. The dorsal surface is longitudinally striated by 5 or 6 lines, which are usually curved. The nucleus is horseshoe-shaped and lies in the posterior half of the body. Length 68µ; diameter 48µ.

Aspidisca hexerisFig. 56.—Aspidisca hexeris.ENLARGE

This form was incorrectly mentioned asMesodiniumsp. by Peck '95:

In the figure given by Quennerstedt there are only 7 ventral cirri. In the Woods Hole form there are 8, 7 of which are anterior, 6 of them about one central one. The eighth cirrus is by itself, near the base of the largest posterior cirrus. These cirri, in spite of their size, are easily overlooked and more easily confused, but by using methylene blue they can be seen and counted.

Aspidisca polystylaStein. Fig. 57.

Aspidisca polystylaFig. 57.—Aspidisca polystyla.ENLARGE

This species is similar toA. hexeris, but is smaller, very transparent, and without the spur-like process on the left edge of the carapace. The chief difference, however, lies in the number of anal cirri. These are 10 in number and they are arranged obliquely as in the preceding species, with the largest one on the right and the smallest on the left. The ventral cirri are 8 in number, and are arranged in two rows, one of which, the right, has 4 cirri closely arranged, the other having 3 cirri close together and one at some distance, near the largest anal cirrus. The peristome, contractile vacuole, and nucleus are similar to the preceding. Length 36µ; width 22µ.

Stein assigns only 7 ventral cirri to this species, but he also describes 2 very fine bristle like cilia (p. 125) and pictures them in figs. 18, 19, 20, and 21 of his Taf. III in the same relative position as my eighth cirrus. I am positive that cilia do not occur on the ventral face of this form, and that the characteristic cirri are the sole locomotor organs.

Key to families of Peritrichida.a.Peristome drawn out into funnel-like process; parasiticFamilySpirochonidæb.Adoral zone and circlet of cilia at opposite end. Adoral zone left-wound. Parasitic.FamilyLichnophoridæ(one genus, *Lichnophora)c.Adoral zone a left-wound spiral. Attached or unattached forms.FamilyVorticellidæ* Presence at Woods Hole indicated by asterisk.

(Gruber '84; Fabre-Domergue '88; Bütschli '88; Wallengren '94; Stevens 1901.)

Small or medium-sized colorless animals, extremely elastic and flexible. The anterior part, bearing the adoral zone, is round or oval in ventral view, and has a flat ventral and a highly arched dorsal surface. The posterior end of the animal is reduced to a stalk-like structure which is broadened at the extremity to form a sucking disk. The surface of this disk and the surface of the peristome may be brought into the same plane by the characteristic bending of the stalk portion. A ciliated girdle is placed at the edge of the sucking disk. A well-developed adoral zone incloses the peristome; it begins at the mouth on the left side and includes nearly all of the peristome in its left-wound spiral, the extremity approaching closely the end near the mouth. The macronucleus is a long-beaded structure, or it may be in several parts connected by strands (Gruber). The contractile vacuole is on the left side in the region of the mouth. Salt water.

Lichnophora macfarlandiStevens. Fig. 58.

The body is elongate; oral disk variable in form, attachment disk clearly defined and constant. The stalk is very contractile and elastic, constantly changing in shape. When detached from the host the animal moves with a very irregular and indefinite motion. When attached it moves freely over the surface on its pedal disk. The latter is bordered by four membranes composed of cilia. A distinct axial fiber extends from the pedal disc to the peristome and gives off a number of branches. This fiber is analogous to the myonemes inVorticella. An indistinct longitudinal furrow can be made out occasionally. The nucleus is in 5 or 6 separate pieces, of which 1 is found in the pedal disk and 1 or 2 in the neck.

On the egg capsules ofCrepidula plana; also reported upon annelids at Woods Hole.

Length 60µ from disk to extremity of the peristomial disk.

Lichnophora macfarlandiFig. 58.—Lichnophora macfarlandi.ENLARGE

This form does not agree in all respects with Stevens's species, but the agreement is so close in other respects that I believe it can be safely identified asL. macfarlandi. The mode of life is different, and the macronucleus is different, there being from 25 to 30 fragments in Stevens's form and only 5 or 6 in the present one. There is, however, the same evidence of chain formation in both of them. The length of the oral cilia in Stevens's form is 18µ in fixed and 30µ in living forms. In the Woods Hole form the cilia are not more than half that length.

Key to the marine genera of Vorticellidæ.Diagnostic characters:Attached or unattached forma of peritrichous ciliates in which the adoral zone seen from above forms a right-wound spiral. A secondary circlet of cilia around the posterior end may be present either permanently or periodically.1.Posterior ciliated girdle permanent around an attaching disk32.Posterior ciliated girdle, temporary during motile stage43.Body cylindrical:(a)With ring of stiff bristles above the ciliated girdleGenusCyclochæta(b)Without accessory ring of bristles; with velumGenusTrichodinaBody conical; general surface ciliatedGenusTrichodinopsis4.No test and no stalkGenusScyphidia5.No test; with stalk containing contractile thread86.No test; with stalk but without contractile threadGenusEpistylis7.With a test; with or without a stalkGenus *Cothurnia8.Individuals solitaryGenus *VorticellaIndividuals colonial; entire colony contractileGenus *ZoothamniumIndividuals colonial; parts only of the colony contractileGenusCarchesium* Presence at Woods Hole indicated by asterisk.

(Bell Animalcule Leeuwenhoek 1675; Ehrenberg '38; Dujardin '41;Stein '51; Cl. & Lach. '58; Greeff '70; Bütschli '88; Kent '81; Stokes '88; etc.)

Medium-sized ciliates of general bell-like form. They may be colorless, or yellow and green through the presence of Zoochlorella. When not contracted, the peristome end is widespread, rarely narrowed. The adoral zone and peristome agree with the details given in the family characteristics. The chief character is the attachment of the posterior end by means of a single, longer or shorter, stalk, which contains a highly contractile thread easily distinguished in the living animal. Another character is the absence of colony formation. Contractile vacuole, single or double, usually connected with a sac-like reservoir. The macronucleus is invariably long and band-formed, with attached micronucleus. Fresh and salt water.

So many species ofVorticellahave been described that the task of collecting data and of arranging the synonyms is extremely irksome and difficult. Stokes enumerates 66 species, inhabiting fresh and salt water, and several other new species have been added since his work. I am impressed with the fact that new species have been created without proper regard for the manifold variations which nearly all of theCiliatashow, and I believe the 66 species might be safely reduced to 12 or 15.

Vorticella patellinaMüller. Fig. 59.

Body campanulate, widest at anterior border, from which it tapers directly to the pedicle. The diameter of the peristome is a little larger than the length of the body. The ciliary disk is but little elevated. The cuticle is not striated and the body plasm is quite transparent. Length 52µ.

Vorticella marinaGreeff. Fig. 60.

The body is conical but variable, and may he short or elongate, so that relative length and breadth offer no chance of identification. In general the body is campanulate. The distinguishing feature is the transverse annulation of the bell.

Small, but common, and grows in small social groups. Length 35µ.

Zoothamnium elegansFig. 61.—Zoothamnium elegans.ENLARGE

Colorless and highly contractile forms growing in small or large colonies. The form and structure of the individuals is not different fromVorticella. The colonies are usually richly branched upon the dichotomous plan and the entire colony is contractile. The main character is that with each division of the individual the stalk also divides, each daughter cell getting one-half of the parent stem. The stems therefore remain in communication, so that a simultaneous contraction results, and the colony as a whole is withdrawn. In some species so-called macrogonidia, or larger sexual individuals, are developed alongside the usual ones. Fresh and salt water.

Zoothamnium elegansD'Udekem '64? Fig. 61.

The bodies are variable—peristomial border widely dilated, tapering and attenuate posteriorly. The pedicle is slender, smooth, and transparent, and branches sparsely at its distal extremity. There are but few zooids (3 to 4). The ciliary disk projects conspicuously beyond the peristomial border. The pharyngeal cleft is very distinct and extends beyond center of body. Length of body 80µ.

Colorless forms of medium size-in some cases they may be green by Zoochlorella. The general structure is similar to that ofVorticella, but the individuals are elongate and occupy houses. The macronucleus is invariably long and band-form. The distinguishing character is the colorless or brownish lorica of quite variable form but always attached. These houses may be finger-formed, with widened center, or widened mouth, or constricted mouth, and the like. Ring-formed swellings are frequently developed. Sometimes the mouth becomes twisted and the lorica is therefore bilateral. The houses are attached either directly to some foreign object or by means of a short stalk. The animals are similarly fastened to the lorica, sometimes directly, sometimes by means of a short stalk. When they contract they draw back to the bottom of the lorica; when expanded they usually stretch out of the mouth opening. In some forms there is an operculum, by means of which the opening of the shell can be closed when the animal is retracted. Fresh and salt water.

The number of species ofCothurniahas become so great that the difficulty in placing forms is almost sufficient to discourage the systematist; as Bütschli well remarks, the variations in the theca have been made the basis of new species so many times that the genus is almost as confused asDifflugiaamong the rhizopods orCampanulariaamong the hydroids. The length of cup, of stalk, the presence of annulations on stalk or cup, etc., have given rise to many specific names, the majority of which I believe can be discarded. According to such differentials the same branch of an alga holding a hundred specimens ofCothurnia crystallinayield 10 or 12 species, whereas they are merely growth stages of one and the same form.

Cothurnia crystallinaEhr. Fig. 62.

Synonyms:Vaginicolla crystallinaEhr., Perty, Eichwald;V. grandisPerty;V. pedunculataEichwald;Cothurnia crystallinaClaparède & Lachmann, D'Udek.;C. giganteaD'Udek;C. maritima,C. crystallinaCohn;C. grandisMeresch.

The form of the cup shows the greatest differences; sometimes it is cylindrical, sometimes elongate thimble-shape, sometimes pouch-shape, corrugated or smooth on the sides, and wavy or smooth on border. Frequently the basal part becomes stalk-like, but this is very short. When present, the stalk may or may not have a knob-like swelling. The animal within the cup may or may not be borne on a stalk, and this stalk may or may not be knobbed. The cups are colorless or brown. The animal is very contractile and may stretch half its length out of the cup or retract well into it. There is no operculum. The length of the cup varies from 70µ to 200µ (C. gigantea;Vag. grandis, etc.). From Entz.

There is nothing to add to Entz's characterization of this species, which is found both in fresh and salt water. The variability of the cup and stalk is quite noticeable in the Woods Hole forms.

Cothurnia crystallinaFig. 62.—Cothurnia crystallina.ENLARGE

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