Stokes.] ^OU [N ov . 5, 



This differs from the preceding species of Opisthostyla in the more 

 conical form and less strongly marked transverse furrows of the body, 

 and in the greater proportionate length of the pedicel. 



Colpoda depressa, sp. nov. (Fig. 14). 



• 



Body ovate, depressed, less than three times as long as broad, slightly 

 widest anteriorly, the frontal border rounded, the right-hand side of 

 the posterior margin slightly and obliquely truncate, the right-hand body- 

 margin somewhat flattened, the left hand side convex ; ventral surface 

 flattened, slightly concave ; cilia of the posterior border longest and most 

 conspicuous, a single cilium occasionally longer than the others ; oral 

 aperture ventral, in the anterior body-half, on the right-hand side of 

 the median line ; the projecting ciliary tuft broad, the cilia fine and 

 appearing like an undulating membrane ; contractile vesicle single, 

 spherical, in the posterior body-half on the right-hand side of the 

 median line ; the cuticular surface roughened by minute elevations ar- 

 ranged in longitudinal rows, except in the oral region, where a long 

 obovate space is comparatively smooth ; endoplasm colorless, granular ; 

 trichocysts numerous, arranged perpendicularly to the cuticular surface ; 

 nucleus ovate, subcentrally located ; anal aperture ventral, on the right- 

 hand side of the posterior extremity. Length of body 3^ to ^i^ inch. 

 Habitat — Standing water, with Sphagnum. Reproduction by transverse 

 fission. 



The most recently formulated generic diagnosis of Colpoda refers to the 

 oral aperture as situated in a cleft like fissure, that orifice in the present 

 form not being so placed but on the flattened ventral surface. It would 

 therefore seem preferable to slightly modify the generic description so as 

 to include the present Infusorian, rather than to form a new generic title 

 upon a difference so slight, especially since the other essential characters 

 are undoubtedly similar. In the previously known species trichocysts 

 have not been observed, neither has the position of the anal aperture been 

 recorded. 



The form here referred to bears some affinity to Anoplirys, but to admit it 

 within that group a change would also be needed in the generic descrip- 

 tion: 



Metopides acuminata, sp. nov. (Fig. 15). 



Body obovate, about twice as long as broad, compressed, the frontal 

 border rounded, the posterior extremity tapering from the body-centre 

 and terminating in a conspicuous acuminate prolongation ; the anterior 

 body-half apparently folded obliquely across the ventral surface, the per- 

 istomal margin strongly ciliate and prolonged beyond the centre of the 

 body to near the right-hand border ; a tuft of long, fine seta? projecting 

 from the posterior acuminatum ; nucleus broadly ovate or subspherical, 

 placed near the body-centre ; contractile vesicle single, near the posterior 



