444 University of California Puhlications in Zoology [Vol. 20 



SUMMARY 



The genus Councilmania is characterized by clear, hyaline pseudo- 

 podia, a nuclear membrane usually not heavily encrusted with peri- 

 pheral chromatin, a karyosome that in the resting phase in the cyst 

 is composed of numerous discrete granules, and by a budding process 

 in which uninucleate amoebulae escape from the cyst in the caecum 

 or colon of the host by a definite pore. The pore is formed near the 

 end of the chromatoidal mass and on or near the chromophile ridge. 



The type species is C. lafleuri found in the human intestine. In 

 this species little peripheral chromatin is found on the nuclear 

 membrane, and the karyosome is composed of numerous coarse 

 granules. Bight chromosomes are found at mitosis. 



C. muris is found in rats and mice. The karyosome is central 

 and composed of 5 to 7 dispersed, fine, uniform granules. Six chromo- 

 somes are present during mitosis. No chromatin blobs occur on the 

 nuclear membrane. 



C. decumani is also found in rats and mice. The nuclear mem- 

 brane is clearly marked with several rather large, distinct blobs, and 

 a karyosome composed of massed granules. Four chromosomes are 

 found at mitosis. 



Zoological Laboratory, 

 University of California. 



Transmitted July 'S3, 19gS. 



