GENUS RA PHID OMONA S. 391 



This animalcule is identified by Stein with both the Chatotyphla annafa and 

 C. aspera of Ehrenberg. As in many other species of the genus, the lorica presents 

 a wide range of individual variation, this being manifested most prominently in con- 

 nection with the more or less extensive development of the spinous processes. 



Trachelomonas caudata, Ehr. sp. Pl. XXI. Fig. 24. 



Lorica elongate-ovate or flask-shaped, two or three times as long as 

 broad, tapering posteriorly and further produced into an acuminate tail-like 

 process, the anterior aperture developed in a neck-like manner, its free 

 margin everted and deeply toothed ; the entire surface, exclusive of the 

 anterior and posterior prolongations, finely and densely hispid. Length 

 1-864" to 1-480". Hab. — Fresh water. 



This species is identified by Stein with the Ckcetoglena caudata of C. G. Ehrenberg. 



Trachelomonas bulla, Stein. 



Lorica elongate-ovate, from two and a half to three times as long as 

 broad, produced anteriorly into a conical, neck-like prolongation ; the 

 surface entirely smooth or beset with minute hispid points which are both 

 finer and less thickly distributed than in T. hispida and T, caudata. Length 

 1-500" to 1-430". Hab. — Fresh water. 



Trachelomonas acuminata, Schm. sp. Pl. XXI. Fig. 26. 



Lorica obovate or flask-shaped, inflated and widest posteriorly, supple- 

 mented in that region by an acuminate and somewhat irregular tail-like 

 process, the anterior extremity produced into a cylindrical, moderately 

 large, obliquely-truncate, neck-like prominence, the surface entirely smooth 

 throughout. Length 1-500". Hab. — Fresh water. 



This animalcule was originally described by Schmarda under the title of Lagenella 

 acuminata, and is refigured and referred to the present generic group by Stein. 



Doubtful Species. 



Pritchard's * Infusoria ' includes the briefest possible diagnosis of two additional 

 species of Trachelofnonas as follows, and without any reference to their original 

 describers : — 



" T. areolata, globose, surface areolated. 



" Zl aspera, similar to the preceding, but its surface covered with rough points." 



Genus VI. RAPHIDOMONAS, Stein. 



Animalcules free-swimming, monoflagellate, moderately contractile ; oral 

 aperture terminal, conducting to a well - defined pharyngeal chamber ; 

 cuticular layer enclosing a large number of variously distributed trichocysts ; 

 contractile vesicle and endoplast conspicuous ; colour green. 



This genus is founded by Stein on the Monas semen of Ehrenberg ; excepting 

 for the presence of numerous and variously distributed trichocysts it closely 

 resembles Ccelomonas. 



