PERITRICHA 



855 



long; parasitic in the oesophagus of Dytiscus marginalis, Acilius 

 sulcatus, Hydaticus transversalis, Graphoderes zonatus and G. bilinea- 

 tus. 



Family 5 Vorticellidae Fromental 



Genus Vorticella Linnaeus. Inverted bell-form; colorless, yellow- 

 ish, or greenish; peristome more or less outwardly extended; pellicle 

 sometimes annulated; with a contractile stalk, macronucleus band- 

 form; micronucleus; 1-2 contractile vacuoles; solitary; in fresh or 

 salt water, attached to submerged objects and aquatic plants or 

 animals. Numerous species. Taxonomy (Noland and Finley, 1931; 



*A^^ 



Fig. 363. a-c, Vorticella campanula (a, X400; b, part of stalk, X800; 

 c, telotroch, X200); d, e, V. convallaria (d, X400; e, XSOO); f-p, V. micro- 

 stoma (f, g, X400; h, X840; i, telotroch, X400; j-p, telotroch-formation 

 in vitro, X270); q, r, V. picta (q, X400; r, X800);s, t, V. monilata (s, 

 X400; t, X800) (Noland and Finley). 



