OF THE OXYTRICHIXA. 



641 



0. proteusa, 0. PeUionella, 0. gihha, 0. GaUina, 0. PuUaster, 0. Lepiis ?, 0. 

 pJatystoma, 0. decumana, and 0. fusca. 



OxYTEiCHA 7'ubra (Trichoda Piscis et 

 T. patens, M.). — Of a brick-red colour ; 

 linear in shape, plane on the imder side, 

 and equally rounded at the ends ; pos- 

 terior end provided with sette. In sea- 

 water. 1-140". 



0. PeUionella (TricJioda PeUionella, M.) 

 (xxix. 21-24). — White, smooth ; slightly 

 depressed, equally rounded at both ends, 

 often broader in the middle; head not 

 separate ; mouth ciliated ; tail provided 

 with setae. Each animalcide has two 

 oval nuclei, and between them a single 

 round vesicle. When self-division com- 

 mences, fom* glands are developed ; and 

 then the vesicle divides. Ehrenberg 

 counted ten cilia anteriorly, and four or 

 five setse posteriorly : the anal outlet is 

 at the base of the setse. In infusions, 

 and throughout Switzerland in swampy 

 ponds along the snow-line of the Alps 

 (Pert^'). Auerbach has seen it encyst 

 itself '(Siebold's Zeitschr. 1854, v. p. 430). 

 1-720" to 1-280". 



Cienkowsky surmises this species, O. 

 gihha, Stylonychia pustulata, and S. lan- 

 ceolata to be one and the same animal- 

 cule in different stages of growth and 

 under different circumstances in respect 

 of food, &c. This notion is favom-ed, he 

 says, by the fact that the animalcule 

 wLich escapes from an encysted S. lan- 

 ceolafa is exactly like S. jJashdafa. 



0. caudata. — Smooth, white ; linear- 

 lanceolate in shape, rounded anteriorly, 

 attenuated posteriorly in the form of a 

 tail, which is provided with setae. Mouth 

 evident. In fresh and sea-water. 1-576" 

 to 1-84". (See ^ty-lo^y chix imstidata.) 



O.platy stoma =■ O. eiiry stoma. — White, 



ovato-oblong, under side flat, yvith. mar- 

 ginal setae ; mouth large and ciliated. It 

 swims with a revolving and vacillating 

 motion, and often upon the back. It 

 creeps upon water-plants, in standing 

 bog- water. 1-240". 



O. yihha (^Trichoda gihha et foeta, M.) 

 (xxv.' 336, 337). — White, lanceolate, 

 ends obtuse, middle enlarged, under side 

 flat, and furnished with two series of 

 setae, and a large roimd moTith. This 

 species resembles O. PeUionella, but is 

 distinguished by its setae, the two or 

 three contractile vesicles, and the nu- 

 cleus. This creature is active, and runs 

 nimbly along aquatic plants in fresh and 

 brackish water. (Fig. 336 an under 

 view, fig. 337 a side view.) 1-240". It 

 is not equivalent to the O. gibha (Duj.). 



0. PuUaster (Trichoda PuUaster, Kerona 

 PuUaster, M.). — Whitish, lanceolate, 

 ends obtuse, ventral surface naked at the 

 middle : the head, indicated by a con- 

 striction, is hairy, like the tail. The 

 mouth narrow. In water-butts, streams, 

 and infusions. 1-430". This form and 

 O. Lepus Perty believes to be mere va- 

 rieties of O. PeUionella. 



O. Cicada {Trichoda Cicada, M.). — 

 Ovate, or almost hemispherical, back 

 furrowed and notched, under sm-face 

 fiat. Upon the surface of stagnant 

 water. 1-1440" to 1-860". 



0. Lepus. — Whitish, elliptical, smooth, 

 flat ; ciliated anteriorly ; provided with 

 setae posteriorly ; the mouth and dis- 

 charging orifices not distinct; and the 

 nucleus imobserved. In standing water. 

 1-540" to 1-96", 



The following additional species are given by Dujardin :- 



O. incrassata. — Ovoid, long, colourless, 

 fringed posteriorly with rigid setae. Not 

 so long as 0. PeUionella, and, unlike it, 

 marine. In the Mediten-anean. 1-350". 



0. Lingua. — Diaphanous, flattened, 

 flexible, elongated, rounded at each end ; 

 without setae or apparent cilia poste- 

 riorly; gi-anules of smface in nearly 

 regulai- rows. In ditch-water with Con- 

 fer vae. 1-212". 



0. amhigua. — Colourless, oval, oblong- 

 depressed in the middle, concave on one 

 side ; margin tumid ; ■v\dth very strong 

 locomotive cilia on the concave sm'face, 

 and with rigid setae behind. In sea- 

 water. 1-350". 



O. radians. — Discoid, red, surrounded 

 by long radiating setae. In salt or brack- 

 ish water. 1-520". 



Perty brings forward the following as new species, belonging to true Oxy~ 

 triclia, characterized by severally having a round posterior extremity : — 



0. proteusa (Perty). — Very long, and I longer than broad. It is sometimes 

 subcylindrical ; nine to twelve times | actually four-sided, with wdde upper and 



2t 



