OF THE EUPLOTINA. 



647 



EuPLOTES Patella. — Lorica large, 

 nearly circular, slightly truncated ante- 

 riorly ; margin transparent, broad ; back 

 elevated, gibbous, and covered with a 

 few delicate smooth striae. The mouth 

 is ciliated on each side ; the oesophagus 

 is near the side, below the middle line, 

 the discharging orifice behind the base 

 of the styles. With Lemuae. 1-280". 



E. Giaron (Trichoda Charon, M.) 

 (xxv. 350-353). — Lorica small, ovate- 

 elliptical, slightly trimcated anteriorly, 

 and ha\dng granular striae on the back ; 

 twenty to forty cilia were counted by 

 Ehrenberg, but no setse; a contractile 

 vesicle and one or more nuclei have been 

 seen. In standing water and infusions. 

 Schneider has seen it in the encysted 

 condition. 1-280". 



E. striatus. — Oblong, elliptical, slightly 

 truncated anteriorly, uncini only upon 

 the posterior part of the body; four 

 smooth striae upon the back. Fission 

 longitudinal. In sea- water, but, accord- 

 ing to Perty, also in freshwater ponds, 

 &c. 1-240.'' 



E. appencUculatus. — Ovate-oblong, ends 

 rounded, provided with oblique styles 

 and four straight setae upon the posterior 

 part of the body. In fresh and sea water. 

 1-240". 



This, says Stein, is the Ploesconia lon- 

 giremis of Dujardin. 



E. trmicatus. — Oblong, with smooth 

 striae ; unequally truncated, and notched 

 anteriorly. It has setae and nimierous 

 uncini. The styles are straight. In sea- 

 water. 1-240". 



Both this and the preceding, Perty be- 

 lieves to be phases of development of 

 E. Charon and striatus. 



E. monostylus. — Elliptical, ends round- 

 ed, no striae. It has a single style, like 

 a tail, but no uncini. In sea-water. 

 1-400". 



E. aculcattis. — Oblong, nearly square, 

 ends rounded; it has two crests upon 

 the back, one bearing a little spine in the 

 middle. In sea- and pond-water. 1-430". 



E. turritus. — Smooth, nearly circular ; 

 it has a long erect spine on the centre of 

 the back. 1-600" to 1-430". 



E. Cimex {Trichoda Cimex, M.). — Ob- 

 long elliptical, and smooth, provided 

 with cilia, styles, and uncini. In sea- 

 water, and, says Perty, in fresh pond- 

 water. 1-430". 



E. viridis. — I^arge (ample), oblong, 

 truncate in front, with a central obtuse 

 tooth, dorsum flat; granules gxeen. 

 1-480". Berlin. 



JE. affinis (Perty) = Ploesconia affinis 

 (Duj.). 



E. subrotundus (Perty) = Ploesconia 

 suhrotunda (Duj.). 



Genus PLCESCONIA (Duj.). — Body oval, more or less flattened, enclosed 

 by an apparent lorica, marked by longitudinal ribs, furnished mostly on one 

 of its plane siu'faces with scattered, fleshy, thick processes in the form of 

 stiff hairs, or of non-vibratile hooks, yet moveable and serving the piu'pose 

 of feet ; on the other surface, with a row of vibratile cilia regularly placed, 

 and becoming finer as they recede from the anterior towards the posterior 

 end, where the mouth is situated, and in the direction of which they vibrate. 



'' In my opinion," adds Dujardin, " a Ploesconia, notwithstanding its ap- 

 parent complexity of structure, is yet an animal as simply organized as those 

 pre\-iously considered — having a simple, fleshy, homogeneous substance, which 

 assumes during life a rather complex form, but loses it at the moment of 

 death, ha\ing no membrane or fibre to sustain it. The cilia or cirrhi, though 

 of varied form, are still of the same nature, and, I should say, of nearly the 

 same consistence. They have a mouth also, but no anus ; vacuoles are formed 

 at the bottom of the mouth, as a result of an impulsive force produced by the 

 vibratile cilia on the surroimding liquid, or they may be hollowed out in any 

 part beneath the surface ; lastly, disseminated through the mass are granules 

 varying in kind, and which I cannot admit as determinate organs nor as ova." 



We much doubt the necessity of creating this new genus, since aU, or 

 nearly all, the species referable to it might be arranged with Euplotes. Stein 

 treats Ploesconia as synonymous ^ith Euplotes (Ehr.), but would retain the 

 former term to designate a new genus represented by PI. Scutum (Duj.), a 

 species, indeed, which is marked by the French natiualist as a doubtful 

 member. 



