66 MANUAL OF HUMAN PROTOZOA 



Somewhat similar to this is Socio edax Klebs 1892 (Fig. 

 14, ^J) which is less frequently seen in faeces. The tropho- 

 zoite is more stumpy and a little smaller, being about 6-15p 

 long. The body is much more rounded in cross-section. 

 The two flagella are nearly equal in length and both are 

 longer than body. Cysts resemble closely those of B. 

 catidatus. 



4. Cercomonas longicauda Dujarclin 1841 



Trophozoites. Body plastic and amoeboid, engulfing 

 bacteria by pseudopodia (Fig. 14, 10). About 5-10m by 5-7m. 

 The nucleus is located near the flagellated anterior end, 

 pyriform in shape, and contains a central endosome. Of the 

 two flagella, the anterior one is about 3-4 times the body 

 length, but the posterior flagellum adheres to body surface 

 and extends a little bevond the body (Fig. 14, H). 



Cysts. Spherical, about 4-6m in diameter. Uninucleate 

 (Fig. 14, 1-). Coarse granules are often grouped around the 

 nucleus. 



5. Copromonas suhtilis Dobell 1908 



Trophozoites. Body elongated pyriform (Fig. 14, 1-3), 

 the pellicle is comparatively thick so that there is little 

 change of body form. It is 7-20|j long. The anterior end is 

 bluntlv pointed, while the posterior end is rounded. A single 

 flagellum takes its origin in the anterior end, near which 

 are seen a contractile vacuole and a reservoir. The vesicular 

 nucleus with a large endosome is near the center of body. 

 At the anterior end, the cytostome opens and is continuous 

 with a long tubular cytopharynx. The cytoplasm usually 

 contains bacteria. 



