CILIATE PROTOZOA (INFUSORIA) 



271 



INFUSORIA 



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

 2(127) Body usually uniformly covered with cilia 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. Moutli closed 



except when taking food. Suborder. Gymnostomina . . 5 



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



Ciha projecting between the plates. . . . Coleps Nitzsch. 

 Representative species Coleps hirtus Ehrenberg 1838. 



Ovate, persistent in shape. Mouth terminal, bordered by tooth-like 

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

 surface. Posterior border usually bearing spines. Length 60 /i- Pond 

 water and old infusions. 



Fig. 458. Coleps hirtus. X 250. (After Conn.) 



(5) Without a shell 7 



7 (12) With tentacle-like processes in addition to the cilia 8 



8 (9) Tentacle process single. Ileonema Stokes. 



Representative species 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 

 subcentral; contractile vacuole posterior. Length 1 20 m- 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 cilia. 



Actinoholus Stein. 

 Representative species [ct'uioboliis radians Stein 1867. 



Body ovate or subglobosc. 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 reprcsentinK indiviilual 

 with mouth downward. Dimensions undetermined. (.■Vftir 

 Calkins.) 



