ENTAMCEB^ OF OTHER MAMMALS 229 



Kofoid, Swezy and Kessel (1923), in their conception of a genus 

 Councilmania, have stated that the common amoebae of rats and 

 mice belong to this genus, in that they possess clear pseudopodia and 

 dispersed karyosomes, and are able in the encysted stage to form buds 

 through a pore, associated with which there may be a problematic struc- 

 ture called the chromophile ridge. They accordingly transfer E. muris 

 decumani and E. muris to the genus Councilmania as C. decumani and 

 C. muris. Furthermore, Kessel (1924) states that in the rat there occurs an 

 amoeba which differs from C. decumani in that it forms granular pseudo- 

 podia, has a compact karyosome, and does not form buds, in which 

 respects it resembles E. coli. It is given the name E. ratti. As explained 

 by the writer (1922rt, 1925) there are no grounds for retaining the genus 

 CouncUmania (see p. 219), so that if Kessel's claims regarding these 

 amoeba? are correct there are to be recognized in rats E. decumani and 

 E. ratti, and in mice E. muris. According to him, E. decumani and 

 E. muris may be transferred to both rats and mice. The writer (1925) 

 feels convinced that much more work will have to be done before the 

 claims regarding these three species can be accepted. It is possible that 

 the amoeba of the rat differs from that of the mouse, but at present it 

 seems safer to regard the amoebse of both rats and mice as E. muris. 



An amoeba with free and encysted stages of the E. coli type was 

 discovered by Brug (1918 a) in rabbits. He named the organism E. cuni- 

 culi. Rudovsky (1923) saw an Entamoeba in hares. A similar form in 

 guinea-pigs was named E. cobayce by Walker (1908), and was again referred 

 to by Chatton (1918c) as E. cavice. It has been seen by the writer in 

 guinea-pigs on several occasions, while the free and encysted forms of an 

 amoeba resembling E. muris were met with in the jerboa in the Sudan. 

 Leger, M. (1918), has also recorded an amoeba of guinea-pigs. He noted 

 that encysted forms of the four-nuclear type were present, while Holmes 

 (1923) has observed cysts like those of E. coli. 



Theobald Smith (1910) discovered amoebse in sections of intestinal 

 ulcers in the large intestine of pigs in America. He did not consider 

 them as pathogenic, but believed they had invaded ulcers which were 

 due to some other cause. They varied in diameter from 8 to 10 microns, 

 and each had a single nucleus with a small central karyosome. Prowazek 

 (1912) described as E. polecki an amoeba found by him in pigs in 

 Saipan. He claimed to have seen the same amoeba in a child also, but 

 this was probably a precystic form of E. histolytica. Prowazek's pig 

 amoeba varied in diameter from 10 to 12 microns, and had a single nucleus 

 which, in some of his figures, is evidently of the entamoeba type. Hart- 

 mann (1913), after examining some of Smith's sections, proposed to name 

 the amoeba E. suis, though admitting its possible identity with 



