Ciliophora 411 



Kent (106; Fig. 7. 46, D), Thuricola Kent (106; Fig. 7. 46, J), Thuricolopsis Stokes 

 (106), and Vaginicola Ehrenberg (106; Fig. 7. 46, A, B). 



Family 8. Vorticellidae. This family includes four genera of typically 

 sessile forms which develop contractile stalks. 



Fig. 7. 48. A, B. Vorticella cousonia Stokes, x700 approx.: extended and 

 contracted specimens; contraction involves the attenuated aboral portion of 

 the body but not the stalk proper (after Faure-Fremiet). C. Carchesium 

 polypiuiuu (Linn.) Kahl, l^ranching pattern of large colony, zooids not 

 shown; diagrammatic (after Kahl). D. Zoothamnium adamsi Stokes, con- 

 tinuous stalk-muscle; zooids about QQfi long (after S.). E. Carchesium lim- 

 neticitni Svec, portion of colony showing separate stalk-muscles in individual 

 stalks; x200 approx. (after Faure-Fremiet). F. Stalked cyst of Zoothanuiiuni 

 arbuscula, x215 approx. (after Furssenko). 



Intrastyhiin Faure-Fremiet (106) includes ectocommensals, either solitary or forming 

 small colonies. In Carchesium Ehrenberg (61, 106; Fig. 7. 48, C, E), the stalk of each 

 zooid in the colony is independently contractile. Vorticella Ehrenberg (11, 106, 159; 

 Fig. 7. 47, A-I; 48, A, B) contains solitary types. In the colonial Zoothamnium Ehren- 

 berg (70, 106, 200; Fig. 7. 48, D, F), there is a continuous stalk-muscle. 



Order 4. Chonotrichida.^ These are ectocommensals, mostly on actively 

 swimming Crustacea. Except for Trichocluma lecythoides (154) from the 



* The life-cycles of several species have been traced in a recent paper by Y. Guilcher 

 (1951. Ann. Sci. Nat., ZooL, Ser. 11, T. 13: 33). 



