SPIROTRICHA, HETEROTRICHA 

 d 



801 



Fig. 342. a, Metopus es, X260 (Kahl); b, M. striatus, X220 (Kahl); 

 c, M.fuscus, X150 (Kahl); d, M. circumlabens, X370 (Powers^; e, Spiro- 

 rhynchus verrucosus, X360 (Kirby); f, Caenomorpha medusula, X200 

 (Blochmann); g, Blepharisma lateritium, X160 (Penard); h, B. persici- 

 num, X290 (Penard); i, B. steini, X340 (Penard); j, Protocruzia piger- 

 rima, X390 (Faria, da Cunha and Pinto); k, Phacodinium metschnicofli, 

 X270 (Kahl). 



elongate or two spherical macro nuclei; a micro nucleus; fresh or salt 

 water (sapropelic). Several species. 



C. medusula P. (Fig. 342, /). 150/x by 130/x; fresh and brackish 

 water. Several varieties. 



Family 3 Spirostomidae Kent. 



Genus Spirostomum Ehrenberg. Elongated; cylindrical; some- 

 what compressed; ectoplasm with highly developed myonemes which 

 are arranged lengthwise independent of ciliary rows, hence highly 

 contractile; yellowish to brown; excretory vacuole terminal large, 

 with a long dorsal canal; macro nucleus either ovoid or chain form; 



