146 



MANUAL OF ELEMENTARY ZOOLOGV 



on red blood corpuscles, which E. coli does not. E. dysenteria. 

 is widespread in tropical and subtropical countries, and is 

 the cause of much sickness and loss of life. An Entamceba 



Fig. 



-The life-cycle of Entamceba 10/i. 



I-III, Binary fission ; 1-4, mulliple fission of a free individual ; a-g- t multiple fission 

 within a cyst. 



a, Rounding off ; 6, division of nucleus, throwing out of chromatin in a granular 

 condition, and appearance of # a vacuole in the cytoplasm ; c, two nuclei in 

 reunited cytoplasm ; d t e, multiple fission ; f t destruction of cyst in a new host ; 

 g, free amcebulEe. 



of small size (E. minuta), and another known as E. tetragena, 

 with a large chromatic central body or "karyosome" in 

 the nucleus, are now known to be forms of E. dysenteria 

 which arise in certain circumstances. Its life-cycle appears 



