366 PROTOZOOLOGY 



cleate, contain a large glycogenous vacuole which stains conspicu- 

 ously with iodine; in intestine of man or mammals. 



I. biitschlii (Prowazek) (7. williamsi P.) (Fig. 171). The tropho- 

 zoite is 6-25ju (average 8-1 5/x) 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 (3-4ju in diameter) visible in vivo ; the large endo- 

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



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Fig. 171. lodamoeba butschlii, X1150 (Kudo). 1, a living amoeba; 2-5, 

 stained trophozoites; 4, 5, somewhat degenerating trophozoites; 6, a fresh 

 cyst; 7-10, stained cysts. 



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

 square; rounded cysts measure about 6-1 5/i 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. It is recognized as a commensal. It does not appear to 

 be as common as the other intestinal amoebae that have already 

 been described above. 



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

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

 probably reservoir host of I. butschlii. 



Genus Endolimax Kuenen and Swellengrebel. Small; vesicular 



