778 



PROTOZOOLOGY 



ciliary rows; peristomal membraneous cilia motile; macronucleus ob- 

 long; in the mantle cavity of the pulmonate snail, Phytia setijer in 

 San Francisco Bay (Kozloff, 1945). 



Genus Ancistrella Cheissin. Elongate; ends rounded; ventral sur- 

 face less convex than dorsal surface; 16-17 longitudinal ciliary rows; 

 ciliation uniform, except anterior-dorsal region, bearing bristle-like 

 longer cilia; 2 adoral ciliary rows on right of peristome, curved dor- 

 sally behind cytostome; contractile vacuole posterior; macronucleus 

 single or divided into as many as 7 parts; micronucleus; commensal. 



A. choanomphali C. (Fig. 330, b). 55-90ju by 18-20/u; in the mantle 

 cavity of Choanomphalus sp. 



Fig. 330. a, Cochliophilus depressus, X600 (Kozloff); b, Ancistrella 

 choanomphali, X840 (Cheissin); c, Boveria teredinidi, X550 (Pickard); d, 

 Plagiospira crinita, X740 (Issel); e, Hysterocineta eiseniae, X250 (Beers); 

 f, Ptychostomum bacteriophilum , X500 (Miyashita). 



