220 HANDBOOK OF PROTOZOOLOGY 



Entamoeba helostomae Brug. In the intestine of Belstoma sp., 

 a water bug. 



Genus Endolimax Kuenen and Swellengrebel. Small 

 parasitic amoeba. The genus is ill-defined. The nucleus pos- 

 sesses a definite membrane and there is a comparatively large 

 irregularly shaped endosome which is composed of chromatin 

 granules embedded in an achromatic ground mass. Several 

 achromatic threads may be seen connecting the endosome with 

 the membrane. One species occurs in the human intestine. 

 Commensal. 



Endolimax nana (Wenyon and O'Connor) (Fig. 87, c, d). 

 Inhabitant of the large intestine of man. The amoeba is, as a 

 rule, sluggish, although lobopodial formation may be quite 

 active. It varies in diameter from 6 to 12 microns. The cyto- 

 plasm is fairly well differentiated into the ectoplasm and 

 endoplasm. The latter contains a nucleus which is difficult to 

 make out in life, and food vacuoles which contain bacteria. 

 The cyst is usually ovoid, measures 8 to 10 microns in diameter, 

 and contains when mature four nuclei. Widely distributed. 

 It is considered as a commensal. 



Endolimax gregariniformis (Tyzzer). In the caecum of the 

 fowls. The small amoeba measures 4 to 12 microns in diameter. 

 Nucleus vesicular with a large endosome. Rounded cysts are 

 uninucleate. 



Endolimax ranarnm Epstein and Ilovaisky (Fig. 87, e, f). 

 In the large intestine of frogs. Small amoeba of the Vahlkampfia 

 type. The vesicular nucleus shows a large endosome, radiating 

 achromatic strands, and small peripheral chromatin granules. 

 The cyst measures up to 25 microns long and contains eight 

 nuclei. 



Endolimax hlattae Lucas. In the colon of the cockroach. 



Genus lodamoeba Dobell. Small amoeba parasitic in the 

 intestine of man and mammals. The vesicular nucleus possesses 

 the following structure, if properly stained: A distinct mem- 

 brane, a large endosome rich in chromatin, a layer of globules 

 which surround the endosome and which do not stain deeply, 

 and achromatic strands between the endosome and the mem- 

 brane. The cysts are ordinarily uninucleate and contain a 



