394 HANDBOOK OF PROTOZOOLOGY 



Trichodina, but with rigid bristles external to the posterior 

 girdle of cilia. 



Cydochaeta spongiUae Jackson (Fig. 169, h). In the inter- 

 stices of the freshwater sponge, Spongilla fluviatilis. 



Cydochaeta domerqui Wallengren (Fig. 169, c). In the 

 integument of freshwater fishes. Body about 55 microns in 

 diameter. 



Genus Trichodinopsis Claparede and Lachmann. Body 

 conical in form; oral end much constricted; body surface 

 covered with long cilia. 



Trichodinopsis paradoxa Claparede and Lachmann (Fig. 

 169, d). Inhabit the gut and respiratory cavity of Cydostoma 

 elegans. When extended about 140 microns long. 



Family 2 Vorticellidae Fromental 



Genus Vorticella Linnaeus. Body inverted bell-form ; color- 

 less, yellowish, or greenish; peristome more or less outwardly 

 extended. Pellicle frequently annulated. Always with a con- 

 tractile stalk. Adoral zone prominent; a single macronucleus 

 curved band-form; one micronucleus; one or two contractile 

 vacuoles. Solitary, never colonial. Free-living in fresh or salt 

 water. Numerous species. Specific identification is very diffi- 

 cult because of variation. 



Vorticella campanula Ehrenberg (Fig. 169, e). Fresh water. 

 Body about 150 microns long; stalk thick, usually 5 to 6 times 

 the body length. 



Vorticella nutans Miiller (Fig. 169,/). Fresh water. About 

 40 to 85 microns long when extended. The body is curved 

 characteristically toward the base of the stalk, 



Vorticella alba Fromentel (Fig. 169, g). Fresh water. 45 

 to 55 microns long. 



Vorticella longifilum Kent (Fig. 169, h). Fresh water. The 

 stalk is 10 to 15 times the body length. 



Vorticella telescopa Kent (Fig. 169, i). Fresh water. With 

 two annular grooves in the posterior part. About 45 to 50 

 microns long. 



Vorticella quadrangularis Kent (Fig. 169, j). Fresh water. 

 Body about 200 microns long. 



Genus Carchesium Ehrenberg. Individuals similar to those 



