AMOEBINA 



461 



composed of chromatin granules embedded in an achromatic ground 

 mass and several achromatic threads connecting the endosome with 

 membrane (Fig. 187, d); commensal in hindgut in man and animals. 

 Several species. 



E. nana (Wenyon and O'Connor) (Fig. 196, a-d). The trophozoite 

 measures 6-18ju in diameter; fairly active monopodal movement by 

 forming a broad pseudopodium; when stationary pseudo podia are 

 formed at different points; endoplasm is granulated and contains 

 bacteria as food particles; the vesicular nucleus, 1.5-3/x in diameter, 

 is composed of a delicate membrane with a few chromatin granules 

 and a large irregularly shaped endosome. 



Fig. 196. a-d, Endolimax nana, X2300 (Kudo) (a, b, living and 

 stained trophozoites; c, d, fresh and stained cysts); e, f, stained tropho- 

 zoite and cyst of E. clevelandi, X3000 (Gutierrez-Ballesteros and Wen- 

 rich); g, h, stained trophozoites of Martinezia baezi, XI 700 (Hegner and 

 Hewitt). 



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. This amoeba 

 is coelozoic in the lumen of the upper portion of colon and is consid- 

 ered to be a commensal. Cytology and life-history (Dobell, 1943). 



E. caviae Hegner. In the caecum of guinea-pigs. Morphology (Heg- 

 ner, 1926; Nie, 1950). 



