HOLOTRICHA 



507 



Fig. 233. a, Holophrya simplex, X800 (Roux); b, Lagynophrya mu- 

 tans, X380 (Kahl); c, Spasmostoma viride, X330 (Kahl); d, Urotricha 

 agilis, X530 (Stokes); e, U. far da, X470 (Lieberkiihn) ; f, g, Plagio- 

 campa marina (f, X400; g, anterior end, X670) (Noland); h, Chilo- 

 phrya utahensis, X840 (Pack); i, C. labiata, X500 (Edmondson); 

 j, Platyophrya lata, X280 (Kahl); k, Stephanopogon colpoda, non- 

 ciliated side, X500 (Kahl); 1, Prorodon discolor, X330 (Butschli); 

 m, Pseudoprorodon farctus, X270 (Roux); n, o, Placus socialis (o, an- 

 terior end view), X530 (Noland). 



Genus Stephanopogon Entz. Somewhat resembles Platyo- 

 phrya; compressed; cytostome at anterior extremity which is 

 drawn out; cytostome surrounded by lobed membranous struc- 

 tures ; salt water. 



S. colpoda E. (Fig. 233, k). Longitudinal striae on 'neck' 4-8 

 in number; 2 contractile vacuoles; 50-70/i long; creeping move- 

 ment; salt water among algae. 



