526 PROTOZOOLOGY 



cytostome ellipsoid with oral basket; macronucleus oval with a 

 micronucleus; 2 contractile vacuoles; fresh water. 



P. vorticella S. (Fig. 240, 1). 80-1 lOju long, cytostome covered by 

 a slit-bearing membrane; with 2 preoral membranes; fresh water. 



Genus Cryptopharynx Kahl. Ellipsoid, anterior third bent to 

 left; ventral surface flat, dorsal surface with hump; spiral inter- 

 ciliary furrows ridged; oval cytostome at anterior end; no cyto- 

 pharynx; dorsal hump yellowish, granulated with gelatinous 

 cover; 2 macronuclei; 1 micronucleus; 2 contractile vacuoles, 

 one posterior and the other toward left side at bend of body. One 

 species. 



C. setigerus K. (Fig. 241, a, h). Elongate ellipsoid; anterior 

 region bent to left; ventral surface flat, dorsal surface with a 

 hump; about 15 ventral ciliary rows; 2 vesicular macronuclei and 

 1 micronucleus, dorso-central; 33-96^ by 21-45^ (Kirby). Kirby 

 found the organism in salt marsh pools (salinity 1.2-9.7 per cent) 

 with purple bacteria in California. 



Genus Chilodonella Strand {Chilodon Ehrenberg). Ovoid; 

 dorso-ventrally flattened; dorsal surface convex, ventral surface 

 flat ; ventral surface with ciliary rows ; anteriorly flattened dorsal 

 surface with a cross-row of bristles; cytostome round; oral 

 basket conspicuous, protrusible; macronucleus rounded; con- 

 tractile vacuoles variable in number; fresh or salt water or ecto- 

 commensal on fish and amphipods. Many species. 



C. cucullulus (Miiller) {Chilodon steini Blochmann) (Figs. 50; 

 241, c-e). 19-20 ventral ciliary rows; oral basket with about 12 

 rods and with 3 preoral membranes; macronucleus oval, a 

 characteristic concentric structure; micronucleus small; body 

 100-300/x long, most often 130-150^ long; fresh and brackish 

 water. 



C. caudata (Stokes) (Fig. 241, /). About 42^ long; standing 

 water. 



C. fluviatilis (S.) (Fig. 241, g). About 50m long; fresh water. 



C. uncinata (Ehrenberg) (Fig. 81). 50-90/x long; about 11 

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

 various freshwater bodies; several varieties. MacDougall (1925) 

 studied conjugation and mutation (p. 164) of this organism. 



C. cyprini (Moroff) (Fig. 241, /i). 50-70m by 30-40^; in integu- 

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

 host body, dies in 12-24 hours. 



