776 PROTOZOOLOGY 



C. mytili de Morgan (Fig. 56). Reniform; 130-220/* by 76-161/x; 

 peristomal groove on the right side; trichocysts conspicuous along 

 frontal margin; macronucleus oval; 2 micronuclei; on the foot of the 

 common mussel, Mytilus edulis. Division and conjugation (Kidder, 

 1933b, c). 



Genus Myxophyllum Raabe. Oval or spheroid; pellicle elastic and 

 flexible ; peristome on posterior right, without undulating membrane; 

 7 macronuclei; a micronucleus ; ciliation uniform; in the slime cover- 

 ing land pulmonates. 



M. steenstrupi (Stein) (Fig. 329, c). 120/i by 100-120/*; on Succinea 

 putris, etc. 



Family 2 Thigmophryidae Chatton and Lwoff 



Genus Thigmophrya Chatton and Lwoff. Elongate ; round or oblong 

 in cross section; cytostome in posterior third; contractile vacuole 

 opens in cy to pharynx; on the gills or palps of lamellibranchs. 



T. macomae C. and L. Elongate ovoid; flattened; ventral surface 

 slightly concave; oral funnel opened; contractile vacuole opens at 

 the bottom of cytopharynx; numerous ciliary rows; about 110m by 

 40m; on the gills of Macoma (TelUna) balthica (Chatton and Lwoff, 

 1923). 



Family 3 Hemispeiridae Konig 



Genus Hemispeira Fabre-Domergue (Hemispeiropsis Konig). 

 Nearly spherical; flattened; longitudinal non-ciliated furrow on ven- 

 tral surface, which encircles thigmotactic posterior cilia; 4-5 cross- 

 furrows of cilia : a huge adoral membrane at anterior end ; macronu- 

 cleus, micronucleus large; contractile vacuole, anterior-right; com- 

 mensal. 



H. asteriasi F.-D (Fig. 329, d). 20-30/x long; ectocommensal on 

 Asterias glacialis (Wallengren, 1895). 



Genus Protophrya Kofoid (Isselina Cepede). Ellipsoid to pyriform; 

 spherical macronucleus; cytostome close to the posterior end. Taxon- 

 omy (Raabe, 1949); ciliation (Chatton and Lwoff, 1949). 



P. ovicola K. (Fig. 329, e, /). About 60m long; in the uterus and 

 brood-sac of the molluscs, Littorina rudis and L. obtusata (Kofoid, 

 1903). 



Genus Ancistruma Strand (Ancistrum Maupas). Ovoid, pyriform 

 or somewhat irregular; flattened; right side with more numerous 

 large cilia than the left; peristome on right side; cytostome near 

 posterior extremity; macronucleus round or sausage-shape, central; 

 a micronucleus; contractile vacuole posterior; commensal in the 

 mantle cavity of various marine mussels. Many species. Morphology, 

 reproduction (Kidder, 1933, 1933a). 



