390 ORDER FLAGELLATA-EUSTOMATA. 



subquadrate, its surface entirely smooth ; the anterior aperture produced as 

 a short, tubular, obliquely projecting neck. Length 1-1200" to 1-750". 

 Hab. — Fresh water. 



This species is identified by Stein with the Lagcnella eucJilora of Ehrenberg, and 

 should apparently retain the specific title conferred upon it by the last-named 

 authority. One example, PL XX. Fig. 19, as represented by Stein, has assumed 

 a quiescent condition within its lorica, and become divided into two equal 

 spheroidal moieties. 



Trachelomonas cylindrica, Ehr. Pl. XXI. Fig. 20. 



Lorica elongate, cylindrical, about three times as long as broad, entirely 

 smooth, anterior aperture plane or produced as a short tubular neck ; 

 colour crimson or purple. Length i-iooo". Hab. — Fresh water. 



The Trachelomonas nigricans of Ehrenberg, coinciding in general form, but 

 having the lorica coloured a deep reddish or blackish brown, is regarded by Perty 

 as an older condition only of the present species. 



Trachelomonas hispida, Pty. sp. Pl. XXI. Figs. 21-23. 



Lorica evenly ovate or elliptical, from a little over one and a half to 

 nearly two and a half times as long as broad, the entire surface finely and 

 evenly hispid ; anterior aperture plane or forming a short cylindrical neck ; 

 walls of peripheral border scarlet or crimson. Length 1-1150" to 1-600". 



Hab. — Fresh water. 



This species is identified by Stein with the CJiatoglena volvocina of Ehrenberg and 

 with the Choncnwnas hispida and C. Schrankii of Max Perty. It is necessary to remark, 

 however, that the enclosed animalcule is represented by Perty as having two long, 

 equal-sized flagella, as in Eiitreptia, instead of a single one as figured by the first- 

 named writer. The lorica of this type is susceptible of a very considerable range of 

 variation, it, in addition to the two contours mentioned in the foregoing diagnosis, 

 being sometimes supplemented, as in T. candata and T. acuminata, with a short, 

 conical, tail-like prolongation. The empty shell has been observed by both Stein 

 and Perty to be finely striate obliquely in cross directions, the intersection of these 

 lines communicating to the entire structure a reticulate appearance. 



Trachelomonas eury stoma, Stein. Pl. XXI. Fig. 27. 



Lorica ovate, bluntly pointed posteriorly, about one and a half times 

 as long as broad, surface smooth, anterior aperture comparatively wide, 

 slightly projecting, its edges crenulate. Length 1-8 12". 



Hab. — Fresh water. 



Trachelomonas armata, Ehr. sp. Pl. XXI. Fig. 25. 



Lorica broadly ovate or elliptical, about one and a quarter times as long 

 as wide ; ten or twelve long claw-like spines projecting from the posterior 

 margin, and a number of short conical ones sometimes disposed around 

 the short tubular anterior aperture ; the intei"vening area smooth ; the free 

 edge of the short neck-like projection sometimes finely toothed ; colour 

 brown. Length, excluding the posterior spines, 1-650". 



Hab. — Fresh water. 



