HOLOTRICHA 777 



A. my tili (Quennerstedt) (Figs. 18; 329, g, h). Oval; dorsal surface 

 convex, ventral surface concave; dorsal edge of peristome curves 

 around the cytostome; peristomal floor folded and protruding; 

 longitudinal ciliary rows on both surfaces; three rows of long cilia on 

 peristomal edges; macro nucleus sausage-form; a compact micro- 

 nucleus anterior; 52-74ju by 20-38/z. Kidder (1933) found it in abund- 

 ance in the mantle cavity of Mytilus edulis at Woods Hole and New 

 York. 



A. isseli Kahl (Fig. 329, *). Bluntly pointed at both ends; 70-88/x 

 by 31-54ju. Kidder (1933) observed it abundantly in the mantle cav- 

 ity of the solitary mussel, Modiolus modiolus, Massachusetts and 

 New York, and studied its conjugation and nuclear reorganization. 



A. japonica Uyemura (Fig. 329, j). Body oval or elongate pyri- 

 form; 55-76(67) /z by 14-29(20) n; subspherical macronucleus con- 

 spicuous; a compact micronucleus; usually a single contractile vacu- 

 ole, posterior; in the mantle cavity of marine mussels; Meritrix 

 meritrix, Paphia philippinarum, Cyclina sinensis, Mactra veneri- 

 formis, M. sulcataria, and Dosinia bilnulata (Uyemura, 1937). 



Genus Eupoterion MacLennan and Connell. Small ovoid ; slightly 

 compressed; cilia short, in longitudinal rows; rows of long cilia in 

 peristome on mid-ventral surface and extend posteriorly, making a 

 half turn to left around cytostome; small conical cytostome lies in 

 postero -ventral margin of body; contractile vacuole terminal; large 

 round macronucleus anterior; a micronucleus; commensal. 



E. pernix M. and C. (Fig. 329, k). 46-48 ciliary rows; 6 rows of 

 heavy peristomal cilia; 38-56/x long; in the intestinal contents of the 

 mask limpet, Acmaea persona; California. 



Genus Ancistrina Cheissin. Ovoid; anterior end attenuated; peri- 

 stomal field along narrow right side; 15-18 ciliary rows parallel to 

 peristomal ridges; cytostome right-posterior, marked with oral ring, 

 with a membrane and a zone of membranellae ; right ridge of peri- 

 stome marked by two adoral ciliary rows; macronucleus anterior, 

 spheroidal; a micronucleus; commensal. 



A. ovata C. (Fig. 329, 1). 38-48/x by 15-20/*; in the mantle cavity of 

 molluscs: Benedictia biacalensis, B. limneoides and Choanomphalus 

 sp. 



Genus Cochliophilus Kozloff. Ovoid and compressed; peristome in 

 right-posterior fourth of the body; membrane-like fine cilia overlie a 

 series of thick cilia from the anterior end of the peristome to cyto- 

 stome; longitudinal rows of cilia; a vesicular micronucleus; an ovoid 

 macronucleus; a contractile vacuole; in molluscs. 



C. depressus K. (Fig. 330, a). About 93/z by 63m by 15m; 52-56 



