CDLIATE PROTOZOA (INFUSORIA.) 



271 



INFUSORIA 



I (208) Cilia present during all stages of existence. . . Class Ciliata . . 2 

 2(127) Body usually uniformly covered with cUia 3 



3 (104) Cilia similar or slightly lengthened about the mouth; no adoral spiral 



zone Order Holotricha . 4 



4 (59) Without an undulating membrane about the mouth. Mouth closed 



except when taking food. Suborder Gymnostomina . 5 



5 (6) With a shell of numerous plates arranged in zones around the body. 



Cilia projecting between the plates. . Coleps Nitzsch. 



Representative species. . . Coleps hirtus Ehrenberg 1838. 



Ovate, persistent in shape. Moutii terminal, bordered by tooth-liice 

 processes, and surrounded by cilia larger than those of the general 

 surface. Posterior border usually bearing spines. Length 60 p.. Pond 

 water and old infusions. 



Fig. 45S. Coleps hirtus. X 250. (After Conn.) 



6 (5) Without a shell. ... 



7 (12) With tentacle-like processes in addition to the cilia 



8 (9) Tentacle process single. 



Representative species. 



Ileonema Stokes. 

 Ileonema dispar Stokes 1885. 



Body flask-shaped, flexible; flattened ventrally, convex dorsally, the 

 latter surface bearing a row of short, hair-like setae. Tentacle-like proc- 

 ess thick at the base, twisted, with a filamentous distal half. Nucleus 

 Eubcentral; contractile vacuole posterior. Length 120 /j. Among algae. 



Fig. 459. Ileonema dispar. X 185. (After Stokes.) 



9 (8) Tentacle processes more than one 10 



10 (11) Tentacles very long and numerous, extending between the cUia. 



Representative species. 



Actinobolus Stein. 

 Actinobolus radians Stein 1867. 



Body ovate or subglobose, the anterior extremity pro- 

 duced as a snout-like projection which carries the mouth 

 and bears the retractile tentacles and cilia. Nucleus 

 band-like; contractile vacuole large. 



Fig. 460. Actinobolus radians. Figure representing individual 

 with mouth downward. Dimensions undetermined. (After 

 Calkins.) 



