32 THE ANIMAL PARASITES OF MAN 



harmless intestinal amoebae of man, whereas the pathogenic species was designated 

 Entamozba histolytica. The history of more recent work is incorporated in the 

 accounts of the entamoebys given below. 



Entamoeba coli, Losch, 1875, emend. Schaudinn, 1903. 

 Syn. : Amoeba coli, Losch, 1875. Enttunceba hominis, Casagr. et Barbag. 1897. 



The amoeboid trophozoite, according to Losch, measures 26 //, to 

 30 IJL and upwards; according to Grassi 8 /A to 22 //, ; according to 

 Schuberg 12 /A to 26 /A. A separation of the body substance into 

 ectoplasm and endoplasm is only perceived during movement. The 

 pseudopodia, which are generally only protruded singly, are broad 



FIG. 3. Entamoeba coli : life-cycle, a e, stages in binary fission ; A D, schizogony, with 

 formation of eight merozoites ; 2 10, cyst formation c r sporogony, with formation of eight 

 nucleate cysts. (After Castellani and Chalmers). 



and rounded at the end (lobopodia) and are hyaline, while the 

 remainder of the body is granular. The ectoplasm is less refractile 

 than the rest of the cytoplasm; it also stains less intensely (fig. i), 

 and is best seen on protrusion of a pseudopodium. Red blood 

 corpuscles are rarely, if ever, found ingested in the cytoplasm. 



The nucleus is vesicular, and is spherical when inactive, measuring 

 5 IJL to 7 /A, with a thick nuclear membrane. In the centre of the 



