180 



PROTOZOOLOGY 



with its attenuated posterior ti]); 1-2 lateral chroniatophores; 

 usually with a stigma; asexual r(>production by binary fission; one 

 of the daughter individuals leaving test as a swarmer, to form a 

 new one; in colonial forms daughter individuals remain attached 



Fig. 87. a, Ochromonas mutabilis, X670 (Senn); b, 0. ludibunda, 

 X540 (Pascher); c, Uroglena volvox, x430 (Stein); d, Uroglenopsis 

 americana, X470 (Lemmermann) ; e, Cyclonexis annularis, X540 

 (Stokes); f, ■Dinohryon sertularia, X670 (Scherffel) ; g, Hyalobryon 

 ramosu7n, X540 (Lauterborn); h, Stylopyxis mucicola, X470 (Bol- 

 ochonzew). 



to the inner margin of aperture of parent tests and there secrete 

 new tests; encystment common; the spherical cysts possess a 

 short process; Ahlstrom (1937) studied variability of North 

 American species and found the organisms occur more com- 

 monly in alkaline regions than elsewhere; fresh water. Numerous 

 species. 



