HOLOTRICHA 733 



ciliary rows; some 7 dorsal bristles; widely distributed in various 

 freshwater bodies; several varieties. Conjugation (MacDougall, 

 1935). 



C. cyprini (Moroff) (Fig. 312, h). 50-70m by 3O-40m; in the integu- 

 ment and gills of cyprinoid fishes; the organism, if freed from the host 

 body, dies in 12-24 hours. Ciliation (Krascheninnikow, 1934). 



C. longipharynx Kidder and Summers. 17-21/1 (average 19m) long; 

 cytopharynx long, reaches posterior end; ectocommensal on amphi- 

 pods, Talorchestia longicornis and Orchestia palustris; Woods Hole 

 (Kidder and Summers, 1935). 



C. hyalina K. and S. 40ju (36-47m) long; ectocommensal on Or- 

 chestia agilis; Woods Hole. 



C. rotunda K. and S. 29m (27-34/z) long; ectocommensal on Or- 

 chestia agilis; Woods Hole. 



Genus Allosphaerium Kidder and Summers. Oval; right side con- 

 cave, left side more or less flat; body highly flattened; arched dorsal 

 surface devoid of cilia; ventral surface slightly concave with 12-27 

 ciliary rows; right and left margin of ventral surface with a pellicu- 

 lar fold; cytostome anterior-ventral, oval or irregular, surrounded by 

 ridge on posterior border, extending to left margin; 3 groups of 

 ciliary membranes extending out of cytostome; macro nucleus oval, 

 central or anterior; a micro nucleus; 2 (or 1) contractile vacuoles; a 

 refractile spherule regularly present in posterior portion of endo- 

 plasm; ectocommensal on the carapace and gills of amphipods. 



A. palustris K. and S. (Fig. 312, i). 46-59/x long; 27 ventral ciliary 

 rows; on Orchestia palustris and Talorchestia longicornis) Woods 

 Hole. 



A. sulcatum K. and S. 24-32m long; 12 ciliary rows; on the carapace 

 of Orchestia agilis and 0. palustris; Woods Hole. 



A. granulosum K. and S. 32-42yu long; rotund; 17 ciliary rows; 

 cytoplasm granulated; on carapace of Orchestia agilis and 0. palus- 

 tris; Woods Hole. 



A. caudatum K. and S. Resembles A. palustris; 35-45ju long; 14 

 ciliary rows; 1 contractile vacuole; ectoplasm at posterior end, drawn 

 out into a shelf; on Orchestia agilis; Woods Hole. 



A. convexa K. and S. 24-36m long; 17 ciliary rows; on the carapace 

 and gill lamellae of Talorchestia longicornis; Woods Hole. 



Family 4 Pycnothricidae Poche 



Ciliation uniform; ectoplasm thick and conspicuous; a furrow or 

 groove connects the cytostome with the anterior end; parasitic in 

 the alimentary canal of mammals. 



