364 



PROTOZOOLOGY 



with an endosome near anterior end; anterior flagellum as long as 

 the body; posterior flagellum shorter, but thicker, in or near cyto- 

 stome; cysts pyriform; 4.5-7/* long; a single nucleus and an oblong 

 area surrounded by fibril; commensal in the lumen of human intes- 

 tine; trophozoites and also cysts occur in diarrhoeic faeces; of com- 

 paratively rare occurrence. Varieties (Hogue, 1933, 1936). 



R. caviae (Hegner and Schumaker, 1928). In the caecum of guinea- 

 pigs; stained trophozoites 4-7 /* by 2.4-3.2/* (H. and S.), 4.4-7.7/* by 

 4-4.3/* (Nie, 1950); stained cysts 3.4-5.2/* by 3.3-3.6/z (H. and S.), 

 4.5-5.7/* by 3.4-3.7/* (Nie). 



Fig. 153. Retortamonas intestinalis, X2300 (a, b, d, Wenyon and 

 O'Connor; c, Dobell and O'Connor; e, g, Kudo; f, Jepps). a, b, organ- 

 isms in life; c, d, stained trophozoites; e, cyst in life; f, g, stained cysts. 



Genus Phyllomitus Stein. Oval; highly plastic; cytostome large 

 and conspicuous; 2 unequal flagella, each originates in a blepharo- 

 plast; fresh water or coprozoic. 



P. undulans S. (Fig. 152, j), Ovoid; 21-27/* long; trailing flagel- 

 lum much longer than anterior one; stagnant water. 



Genus Colponema Stein. Body small; rigid; ventral furrow con- 

 spicuous, wide at anterior end; one flagellum arises from anterior end 

 and the other from middle of body; fresh water. 



C. loxodes S. (Fig. 152, k). 18-30/* by 14/* cytoplasm with refractile 

 globules. 



Genus Cercomonas Dujardin. Biflagellate, both flagella arising 

 from anterior end of body; one directed anteriorly and the other 

 runs backward over body surface, becoming a trailing flagellum; 

 plastic; pyriform nucleus connected with the blepharoplast of 

 flagella; spherical cysts uninucleate; fresh water or coprozoic. 



