400 



PROTOZOOLOGY 



the endosome and membrane (Fig. 187, c); cysts ordinarily uninu- 

 cleate, contain a large glycogenous vacuole which stains conspicu- 

 ously with iodine; in intestine of man and mammals (Dobell, 1919). 

 I. butschlii (Prowazek) (7. williamsi P.) (Fig. 195). The tropho- 

 zoite is 6-25/x (average 8-1 5/z) in diameter; fairly active with pro- 

 gressive movement, when fresh; cytoplasm not well differentiated; 

 endoplasm granulated, contains bacteria and yeasts in food vacu- 

 oles; the nucleus (3-4/x in diameter) visible in vivo; the large endo- 

 some about \ the diameter of nucleus, surrounded by small spherules. 



.;. ' ® 



w 



© 



Fig. 195. Iodamoeba butschlii, X1150 (Kudo). 1, a living amoeba; 2-5, 

 stained trophozoites; 4, 5, somewhat degenerating trophozoites; 0, a fresh 

 cyst; 7-10, stained cysts. 



The cysts are spherical, ovoid, ellipsoid, triangular, pyriform or 

 square; rounded cysts measure about 6-1 5/* in the largest diameter; 

 a large glycogen body which becomes conspicuously stained with 

 Lugol's solution (hence formerly called "iodine cysts") persists; 

 nucleus with a large, usually eccentric endosome. 



The trophozoites and cysts are ordinarily present in diarrhoeic 

 faeces, while the formed faeces contain cysts only. This amoeba ap- 

 parently lives in the lumen of the colon and does not seem to attack 

 host's tissues and is, therefore, considered to be a commensal. No- 

 menclature (Dobell, 1919); nuclear structure (Wenrich, 1937a). 



I. suis O'Connor. In colon of pig; widely distributed; indis- 

 tinguishable from I. butschlii; it is considered by some that pigs are 

 probably reservoir host of I. butschlii. 



Genus Endolimax Kuenen and Swellengrebel. Small; vesicular 

 nucleus with a comparatively large irregularly shaped endosome, 



