354 PROTOZOOLOGY 



granules attached to the nuclear membrane (Fig. 164, h). It was es- 

 tablished by the two Italian authors who were unaware of the exist- 

 ence of the genus Endamoeba (p. 351). Numerous species in 

 vertebrates and invertebrates. 



E. histolytica Schaudinn (Figs. 167; 168). The trophozoite is a very 

 active amoeba and measures about 15-35jLi in diameter; cytoplasm 



■xmi 



'^''' 

 R 



<:> 



Fig. 167. Entamoeba histolytica, X1150 (Kudo). 1, a living trophozoite; 

 2-4, stained trophozoites; 5, a fresh cyst; 6-9, stained cysts. 



usually well dijEferentiated ; eruptive formation of large lobopodia, 

 composed largely of ectoplasm; when fresh, active monopodial 

 progressive movement; the vesicular nucleus appears in life as a 

 ring, difficult to recognize; food vacuoles contain erythrocytes, tissue 

 cell fragments, leucocj^es, etc.; stained nucleus shows a membrane, 

 peripheral chromatin granules, a centrally located small endosome, 

 and an indistinct network with a few scattered chromatin granules. 

 The trophozoite multiplies by binary fission. The amoeba lives 

 normally in the tissues of the intestinal wall of man and brings 

 about characteristic ulceration of the colon which is often accom- 

 panied by symptoms of amoebic dysentery. Through the portal vein, 



