528 PROTOZOOLOGY 



Genus Allosphaerium Kiddor et Summers. Oval; right side 

 concave, 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 margins of ventral surface 

 with a pellicular fold; cytostome anterior- ventral, oval or irregu- 

 lar, surrounded by ridge on posterior border, extending to left 

 margin; in front of it the peristome; 3 groups of ciliary membranes 

 extending out of cytostome; macronucleus oval, central or an- 

 terior; a micromicleus; 2 (or 1) contractile vacuoles; a refractile 

 spherule regularly joresent in posterior portion of endoplasm; 

 ectocommensal on carapace and gills of amphipods. 



A. palustris K. et S. (Fig. 241, i). 46-59^i long; 27 ventral 

 ciliary rows; on Orchestia palustris and Talorchestia longicornis; 

 Woods Hole. 



A. sulcatum K. et S. 24-32/x long; 12 ciliary rows; on carapace 

 of Orchestia agilis and 0. palustris; Woods Hole. 



A. granulosum K. et S. 32-42^i long; rotund; 17 ciliary rows; 

 cytoplasm granulated; on carapace of Orchestia agilis and 0. 

 palustris; Woods Hole. 



A. caudatum K. et S. Resembles A. palustris; 35-45^ long; 

 14 cihary rows; 1 contractile vacuole; ectoplasm at posterior end, 

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



A. convexa K. et S. 24-36iu long; 17 ciliary rows; on 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 alimentary canal of mammals. 



Genus Pycnothrix Schubotz. Large, elongate; with broadly 

 rounded anterior and narrowed posterior end; somewhat flat- 

 tened; short thick cilia throughout; ectoplasm thick; macro- 

 nucleus spherical, in anterior 1/6; micronucleus(?) ; 2 longitudinal 

 grooves, one beginning on each side near anterior end, united at 

 the notched posterior end; a series of apertures in grooves con- 

 sidered as cytostomes; at posterior 1/3, a pore gives rise to 

 branching canals running through endoplasm, and is considered 

 as excretory in function; in colon of Procavia capensis and P. 

 hrucei. One species. 



P. monocystoides S. (Fig. 242, a). 300At-2 mm. long. 



