AMOEBINA 367 



nucleus with a comparatively large irregularly shaped endosome, 

 composed of chromatin granules embedded in an achromatic ground 

 mass and several achromatic threads connecting the endosome with 

 membrane (Fig. 164, d) ; commensal in hindgut in man and animals. 

 Several species. 



E. nana (Wenyon and O'Connor) (Fig. 172). The trophozoite 

 measures 6-15jli in diameter; fairly active monopodial movement by 

 forming a broad pseudo podium; when stationary pseudo podia are 

 formed at different points; endoplasm is granulated and contains 

 bacteria as food particles; the vesicular nucleus, 1.5-3)u in diameter, 

 is composed of a delicate membrane with a few chromatin granules, 

 and a large irregularly shaped endosome. 



Fig. 172. Endolimax nana, X1150 (Kudo). 1, a living amoeba; 2-4, 

 stained amoebae; 5, a fresh cyst; 6, a stained cyst. 



The cyst is usually ovoid; young cyst contains 1 or 2 nuclei; mature 

 cyst with 4 nuclei; indistinctly outlined glycogen body may be 

 present while immature; dimensions 5-12/x (majority 7-10/i) in 

 diameter. 



The trophozoites are found in diarrhoeic or semifluid faeces to- 

 gether with the cysts, and formed faeces contain cysts only. This 

 amoeba is coelozoic in the lumen of the upper portion of colon and is 

 considered as a commensal. 



E. gregariniformis (Tyzzer). In caecum of fowls; 4-12)u in diam- 

 eter; cysts uninucleate. 



E. ranarum Epstein and Ilovaisky. In colon of frogs; cyst octo nu- 

 cleate, up to 25ju in diameter. 



E. blattae Lucas. In colon of cockroaches; 3-15^ long; cyst with 

 more than one nucleus. 



Genus Dientamoeba Jepps and Dobell. Small amoeba; number of 

 binucleate trophozoites often greater than that of uninucleate 

 forms; nuclear membrane delicate; endosome consists of several 

 chromatin granules embedded in plasmosomic substances and 

 connected with the membrane by delicate strands (Fig, 164, e); in 

 colon of man. 



