Part 7

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 in _Vorticella_. 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 of _Crepidula plana_; also reported upon annelids at Woods Hole.

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

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 as _L. 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 3 permanent around an attaching disk

2. Posterior ciliated girdle, 4 temporary during motile stage

3. Body cylindrical:

(a) With ring of stiff bristles Genus _Cyclochæta_ above the ciliated girdle

(b) Without accessory ring of Genus _Trichodina_ bristles; with velum

Body conical; general Genus _Trichodinopsis_ surface ciliated

4. No test and no stalk Genus _Scyphidia_

5. No test; with stalk containing 8 contractile thread

6. No test; with stalk but without Genus _Epistylis_ contractile thread

7. With a test; with or without Genus *_Cothurnia_ a stalk

8. Individuals solitary Genus *_Vorticella_

Individuals colonial; Genus *_Zoothamnium_ entire colony contractile

Individuals colonial; parts Genus _Carchesium_ only of the colony contractile

* Presence at Woods Hole indicated by asterisk.

Genus VORTICELLA (Linnæus 1767) Ehr. '38

(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 of _Vorticella_ have 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 the _Ciliata_ show, and I believe the 66 species might be safely reduced to 12 or 15.

Vorticella patellina Müller. 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 marina Greeff. 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.

Genus ZOOTHAMNIUM (Bory de St. Vincent 1824) Stein '38, '54.

Colorless and highly contractile forms growing in small or large colonies. The form and structure of the individuals is not different from _Vorticella_. 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 elegans D'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.

Genus COTHURNIA (Ehr. '31) Clap. & Lach. '58.

Colorless forms of medium size-in some cases they may be green by Zoochlorella. The general structure is similar to that of _Vorticella_, 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 of _Cothurnia_ has 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 as _Difflugia_ among the rhizopods or _Campanularia_ among 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 of _Cothurnia crystallina_ yield 10 or 12 species, whereas they are merely growth stages of one and the same form.

Cothurnia crystallina Ehr. Fig. 62.

Synonyms: _Vaginicolla crystallina_ Ehr., Perty, Eichwald; _V. grandis_ Perty; _V. pedunculata_ Eichwald; _Cothurnia crystallina_ Claparède & Lachmann, D'Udek.; _C. gigantea_ D'Udek; _C. maritima_, _C. crystallina_ Cohn; _C. grandis_ Meresch.

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 imberbis Ehrenberg, var. curvula Entz. Fig. 63.

Synonyms: _C. imberbis_ Kent et al.; _C. curvula_ Entz; _C. socialis_ Gruber?

The lorica is swollen posteriorly, narrowest at the oral margin, bent on its axis and is supported on a short stalk. It is perfectly smooth and without annulations. The animal itself has no definite stalk. When fully expanded the animal emerges but slightly from the margin of the cup. Fresh and salt water. On red algæ. Dimensions of Woods Hole form: Cup 50 to 55µ long; greatest diameter 22µ; length of stalk 4 to 5µ.

Cothurnia nodosa Claparède & Lachmann. Fig.64.

A. Smooth cup.--_Cothurnia maritima_ Ehr., Eichwald, Stein, Kent.

B. Cross-ringed cup.--_C. pupa_ Eichwald, Stein, Cohn; _C. nodosa_ Cl & L.; _V. crystallina_ Entz '78; _C. pontica_ Meresch., Kent; _C. cohnii_ and _pupa_ Kent; _C. longipes_ Kellicott '94.

The cup is elongated, swollen centrally, tapering at oral end and conical at base or rounded. Oral opening either circular or elliptical. Cross rings may or may not be present, and the cup is either smooth or annulate. Length of cup 70µ to 80µ. The stalk which supports the cup is extremely variable in length. The animal is borne upon a stalk of variable length within the cup.

Entz states that the many variations which this species exhibits run into each other so gradually that he does not believe it wise to separate them. The Woods Hole forms which I found on algæ of various kinds were nearly of a size, and did not vary much from the one figured. Kellicott '94 described a _Cothurnia_ from Woods Hole under the name of _C. longipes_, which I believe is only a long-stemmed variety of _C. nodosa_. My form has the following dimensions: Cup 75µ; cup stalk 38µ; animal stalk 14µ.

KEY TO FAMILIES OF SUCTORIA.

a. Unattached forms; ventral cilia _Hypocomidæ_ present; one suctorial tentacle

b. Attached forms; thecate and _Urnulidæ_ athecate tentacles simple, one or two in number

c. Thecate; posterior end of cup _Metacinetidæ_ drawn out into stalk; walls perforated for exit of tentacles

d. Stalked or unstalked; globular; _Podophryidæ_ tentacles of different kinds, some (2 genera *_Ephelota_, knobbed, others pointed *_Podophrya_)

e. Naked or thecate; stalked or not; _Acinetidæ_ tentacles numerous, usually knobbed and all alike

f. Naked; athecate; tentacles _Dendrosomidæ_ numerous, all alike, knobbed and grouped in tufts. They may be simple or branched.

g. Sessile forms resting on basal _Dendrocometidæ_ surface or on a portion raised like a stalk; tentacles many; short and knobbed; distributed on apical surface or localized on branched arms

h. Stalked or sessile; tentacles _Ophryodendridæ_ long, rarely knobbed, supported on proboscis-like processes

* Presence at Woods Hole indicated by asterisk.

Genus PODOPHRYA Ehr. '33.

(Bütschli '88; Stein '59; Perty '52; Cienkowsky '55; Quenn. '69; Hertwig '77; Maupas '81.)

The body is globular, with tentacles radiating in all directions. The tentacles may be very short or very long. The stalk also is either short or long, and some species form stalks but rarely (_P. libera_). The macronucleus is centrally placed and globular to ovoid in form. The contractile vacuole is usually single. Reproduction takes place by division; the distal half developing cilia and becoming a swarm-spore. Fresh and salt water.

Podophrya gracilis, n. sp. Fig. 65.

Of all the _Podophrya_ that have been described not one approaches this minute form in the relative length of the stalk. The body is spherical and is covered with short capitate tentacles. The stalk is extremely slender, bent, and without obvious structure. There are one or two contractile vacuoles in the distal half of the body. The nucleus is small and is situated near the insertion-point of the stalk. Reproduction not observed. Diameter of body 8µ; length of stalk 40µ. Only one specimen seen.

Genus EPHELOTA Str. Wright '78.

(Bütschli '88; Ishikawa '96; Sand '98.)

Small to medium-sized and large forms; colorless to brown. The body is globular or oval or wedge-shape, sometimes quadrangular. The stalk is variable, sometimes 1 mm. in length. The diameter of the stalk increases from the point of attachment to the body of the animal; it is usually striated either longitudinally or transversely, or both. The tentacles are of two kinds and are usually confined to the anterior half of the body. Some are long and sharp-pointed and adapted for piercing; others are short, cylindrical, usually retracted and capitate, adapted for sucking. Contractile vacuoles vary from one to many. The macronucleus is nearly central in position and usually of horseshoe shape, but is frequently branched and irregular. Reproduction is accomplished by external multiple budding, usually from the anterior half of the body. Salt water.

Ephelota coronata Str. Wright. Fig. 66.

Synonyms: _Hemiophrya gemmipara_ S. K.; _Podophrya gemmipara_ Hertwig.

The body is spheroidal, ovate, or pyriform, with numerous sharp-pointed tentacles and a few straight, uniform tentacles. The stalk is about three times the length of the body and tapers from its widest part at the insertion in the body to the narrowest part at the point of attachment. It may or may not be longitudinally striated. This is one of the commonest of the _Suctoria_ found at Woods Hole. It is usually present on Campanularian hydroids, but may be found on algæ and Bryozoa.

Length of body 90µ to 200µ.

Genus ACINETA Ehr. '33, Bütschli '88.

(Stein '54, '59; Claparède & Lachman '58; Quennerstedt '67; Hertwig '76; Mereschowsky '79; Entz '84; Kent '81; Maupas '83; Gruber '84; Gourret & Roeser '86, and others.)

Small to medium-sized forms. The distinguishing feature is that the stalk is swollen at the distal extremity to form a cup or basin in which the animal rests. The cup may be developed until the body is nearly inclosed. The macronucleus is spherical or band form. The contractile vacuole is usually single. Budding, so far as known, is endogenous. Fresh and salt water.

Acineta divisa Fraipont '79. Fig. 67.

This extremely graceful form is common on Bryozoa at Woods Hole. The cup is shaped like a wine glass and is specifically characterized by a cup-formed membrane upon which the animal rests. The animal thus has the appearance of being suspended on the edge of the cup. The stalk is slender and about 4 times the length of the body. The tentacles are all capitate and distributed, and about 2-1/2 times the body length. They sway back and forth very slowly. The nucleus is spherical and central in position. The contractile vacuole lies near the periphery.

Length of body 27µ; of stalk 100µ; of extended tentacle 65µ.

Acineta tuberosa Ehr. Fig. 68.

Large forms of _Suctoria_ with tentacles arranged in fascicles. The stalk is variable in length and the cup is frequently so delicate that it can barely be made out. A specific characteristic is the break in continuity of the cup at different points, and through these places the tentacles emerge in bundles. The tentacles are capitate and in the Woods Hole form, 15 in number in each of the two bundles. The endoplasm is granular and yellowish in color. The coloring matter is frequently arranged in patterns. The nucleus is spheroidal. The contractile vacuole is in the anterior third of the body about midway between the bundles of tentacles. Reproduction not observed.

Length of body 330µ.

Genus TRICHOPHRYA Clap. & Lach. '58.

(See Kent '81; Entz '84; Bütschli '88; Sand 1901.)

Small forms to medium size; no cups or stalks. The body is spherical to elongate, usually, however, more or less irregularly lobed and changeable. The tentacles are in fascicles which are usually borne upon lobed or swollen places. The body is always more or less spread out. Contractile vacuoles variable. The macronucleus is spherical, elongate, band-formed or horseshoe-shaped. Reproduction takes place by endogenous budding, and the swarm spores are flat or lenticular with a distinct ciliary girdle. They are frequently parasitic. Fresh and salt water.

Trichophrya salparum Entz '84. Fig. 69.

Bütschli '88; Schewiakoff '93; _Trichophrya ascidiarum_ Lachmann '59; René Sand 1901.

The body is somewhat cup-form, with a large, flat base. The anterior border is rounded, each of the ends being somewhat truncate and carrying a bundle of tentacles all capitate and similar. These may be continued internally as far as the nucleus (Sand). The cytoplasm is uncolored, but may contain some brilliant granules. The nucleus is granular, and spherical, band or horseshoe formed.

This species was found by Dr. G. Hunter on the branchial bars of the Ascidian _Molgula manhattensis_, where great numbers of them are often parasitic.

LIST OF REFERENCES.

AUERBACH, L. '54. Ueber Encystierung von Oxytricha pellionella. Zeit. wiss. Zool., V, 1854.

---- '55. Ueber die Einzelligkeit der Amoeben. Zeit. wiss. Zool., VII, 1855.

BALBIANI E. G. '61. Recherches sur les phénomènes sexuelles des Infusoires. Jour. de la physiol:, IV, 1861.

---- '85. Sur un Infusoire parasite du sang de l'Aselle aquatique. Rec. zool. Suisse, II, 1885.

BERGH, R. S. '79. _Tiarina fusus_ Cl. & Lach. Vid. Med. f. d. Nat. Foren. Kjobenhavn.

---- '82. Der Organismus der Cilioflagellaten. Morph. Jahr., VII, p. 177.

BRADY, H. B. '79. Report on the Foraminifera dredged by H. M. S. _Challenger_ during the years 1873-1876. Challenger Reports, Zoology, IX.

BRANDT, K. '96. Die Tintinnodeen. Bibliot. Zoolog., XX, 1896.

BÜTSCHLI, O. '76. Studien über die ersten Entwickelungsvorg. der Eizelle, die Zelltheilung, und die Conjugation der Infusorien. Abhand. der Senck. naturf. Ges. Freiburg, X, 1876.

---- '83-'88. Die Protozoen. Bronn's Klassen u. Ord. des Tierreichs.

CARPENTER, W. B. '56. Researches on the Foraminifera. Phil. Trans. (2), p. 547.

CARTER, H. J. '56. Notes on the fresh-water Infusoria of the island of Bombay. Ann. Mag. Nat. Hist. (2), XVIII.

---- '63. On the coloring matter of the Red Sea. Id. (3), XI.

---- '63a. On _Amoeba princeps_ and its reproductive cells. Id. (3), XII.

---- '64. On fresh-water Rhizopods of England and India. Id. (3), XIII, p. 13.

---- '65. On the fresh- and salt-water Rhizopods of England and India. Id. (3), XV, p. 277.

CIENKOWSKY, L. '55. Bemerkungen über Stein's Acinetenlehre. Bull. Phys. Math. Acad., St. Petersburg, XIII, p. 297 (also in Ann. Mag. Nat. Hist. (3), XIII).

---- '55. Ueber Cystenbildung bei Infusorien. Zeit. wiss. Zool., VI, p. 301.

---- '61. Beiträge zur Kenntniss der Monaden. Arch. f. mik. Anat., I, 1865, p. 203.

CLAPARÈDE, E. '54. On _Actinophrys sol_. Ann. Mag. Nat. Hist. (2), XV, 1854.

---- '60. Recherches sur les annélides, etc., observés dans les Hébrides. Mém. Soc. phys. d'hist. nat., Genève, XVI, 1860.

---- '67. Miscellanées zoologiques. Ann. d. sc. nat. zool. (5), VIII, 1867.

CLAPARÈDE ET LACHMANN '58-'60. Etudes sur les Infusoires et les Rhizopodes. Mém. Inst. genèvoise, V, VI, VII.

COHN, F. '54. Beiträge z. Entwicklungsges. der Infusorien. Zeit. wiss. Zool. III, 1851; IV, 1853.

---- '57. Ueber Fortpflanzung von _Nassula elegans_ Ehr. Zeit. wiss. Zool., IX, 1857, p. 143.

COSTE, M. '64. Développement des Infusoires ciliés dans une macération de foin. Ann. d. ac. nat. zool.(5), II.

DADAY, E. v. '86. Ein kleiner Beitrag der Infusorien-Fauna des Golfes v. Neapel. Mitt. Zool. St. Neap., VI, p. 481.

---- '88. Monographie der Familie der Tintinnodeen. Mitt. Zool. St. Neap., VIII, p. 473.

DAVIS, J. '79. On a new species of Cothurnia. Jour. Roy. Mic. Soc., II, 1879.

DUJARDIN, F. '35. Recherches sur les organismes inférieures. Ann. d. sc. nat. zool. (2), IV, p. 343.

---- '41. Histoire naturelle des Zoophytes infusoires. Paris, 1841.

EHRENBERG, C. G. '31. Ueber die Entwickelung und Lebensdauer d. Infusionsthiere. Abhand. d. Berlin Ak., 1831, p. 1.

---- '38. Die Infusionsthierchen als vollkommne Organismen. Leipzig, 1838.

ENGELMANN, Th. W. '78. Zur Physiologie der Contractilen Vacuolen der Infusionsthiere. Zool. Anz., I, p. 121.

ENTZ, G. '84. Ueber Infusorien d. Golfes v. Neapel. Mitt. Zool. St. Neap., V, p. 289.

---- '85. Zur naheren Kenntniss der Tintinnodeen. Mitt. Zool. St. Neap., VI, p. 185.

FABRE-DOMERGUE, P. '85. Note sur les Infusoires ciliés de la baie de Concarneau. Jour. d. l'anat. et de la phys., XXI, p. 554.

---- '91. Matériaux pour servir a l'histoire des Infusoires ciliés. Ann. d. mic., III, 1890-91, p. 49.

FOL, H. '83. Further contribution to the knowledge of the Tintinnodea. Ann. Mag. Nat. Hist. (5), XII, p.73.

FRANCÉ, R. H. '97. Der organismus der Craspedomonaden. Budapest.

FROMENTEL. E. DE. '74. Etudes sur les microzoaires, etc. Paris, 1874.

GOURRET ET ROESER. '88. Contributions à l'étude des Protozoaires de la Corse. Arch. d. biol., VIII p. 139.

GREEFF, R. '66. Ueber einige in der Erde lebende Amoeben und andere Rhizopoden. Arch. f. mik. Anat., II, p. 299.

---- '70. Untersuchungen ueber den Bau u. d. Naturgeschichte d. Vorticellen. Arch. f. Naturges., XXXVI, XXXVII.

---- '71. Ueber die Actinophryens oder Sonnenthierchen des Süssenwassers als echte Radiolarien. Sitz. Ber. d. Niederrh. Ges. i. Bonn, XXVIII, p. 4.

---- '75. Ueber Radiolarien u. Radiolarienartige Rhizopoden des Süssenwassers 2. Arch. f. mik. Anat., XI.

---- '88. Studien über Protozoen. Sitz. Ber. Ges. z. Bef. d. ges. Nat., Marburg, 1888, p. 91.

GRENACHER, H. '68. Ueber _Actinophrys sol_ Ehr. Verh. phys.-med. Ges. Freiburg (n. F.), I.

GRUBER, A. '83. Beobachtungen an _Chilodon curvidentis_ n. sp. Festschr. 56. Vers. Deutsch. Naturf. gewid. v. d. Naturf. Ges. Freiburg, II, p. 1.

---- '84. Die Protozoen des Hafens v. Genua. Nova Act. d. K. Leop.-Car. Deutsch. Akad. d. Naturf., XLVI, p. 475.

---- '87. Ueber der Bedeutung der Conjugation bei den Infusorien. Ber. d. Naturf. Ges. Freiburg, II, p. 31.

HÆCKEL, E. '73. Zur Morphologie der Infusorien. Jena Zeit., VII, p. 516.