160 PROCEEDINGS OF THE ACADEMY OF [PaRT I 



is itself a constituent part of a long, pale, grayish rod-like mass, 

 which stains red with carmine, but much less easily than does the 

 spherical nucleus. Sometimes, there are two of these cylindrical 

 masses, with the nucleus in one of them only, or the cylindrical 

 mass may contain, not one nucleus in its center (as is most gener- 

 ally the case, (Plate VIII, fig. 63), but several, regularly disposed, 

 for instance three at equal distances, or four in two groups which 

 are separated by a longer interval (Plate VIII, fig. 62). 



Euglena pseudomermis slowly progresses forward in a straight 

 line, then suddenly stops, and takes up its course again, slightly 

 shaken by the beating of the flagellum. The little moving needle 

 looks rigid, not deformable, but is not so in fact; from time to time 

 it is seen to curve feebly, or become deformed by longitudinal un- 

 dulations, very weak indeed but adding in a remarkable manner 

 to the resemblance to a small Nematode. 



The only two Euglenae which I could find in literature to have 

 any similarity to Euglena pseudomermis are Eugl. acus Ehrenberg 

 and Eugl. acutissima Lemmermann. But both are relatively much 

 less lengthened, fusiform rather than like real needles; and besides, 

 they have characteristic green chromatophores. I long hesitated 

 as to the genus to which this little Flagellate might belong. Menoi- 

 dium differs from Euglena in the complete absence of chromato- 

 phores. Would it have been better to make a Menoidium of this 

 species? 



Trentonia flagellata Stokes. Plate VIII, flgs. 64-67 a, b. 



In the analytical table which concerns the group of the Chloro- 

 monadinae, as given by Pascher (27, p. 177), the subdivision of the 

 colored forms is into three genera, which are distinguished from 

 each other as follows: 



I. No highly refractive trichocyst-like corpuscles in the peripheral 

 plasma layer. 



A. Cells changeable in form, more or less pyriform, narrower 



at the anterior end. Vacuolaria. 



B. Cells less changeable in form; at the anterior end diagonally 



truncate, long and narrowed posteriorly. Trentonia. 



II. In the peripheral plasma, highly refracting trichocyst-like cor- 

 puscles. Gonyostomum. 



Vacuolaria would then differ from Tj-entonia only in having a 

 more pronounced change of form, and also by some difference in 

 shape, the narrower part being anterior whilst in Trentonia it is 



