1923] Kofoid-Swezy-Kessel: On the Genus CouncUmanki 43:3 



either with or without buddiny:, occur in the stools of the host, though 

 not regularly. In rodent hosts they are much more sporadic than 

 in the human one. 



The type species is Coii,ncilmania lafleuri Kofoid and Swezy 

 (1921). Other species may be expected to be found in the wild 

 rodents. 



This species prior to 1921 was confused with Endamoeba coli 

 (Loesch) Schaudinn, and since its publication has been included in 

 the synonymy of E. coli by Wenyon (1922), Brumpt (1923), and 

 others, we believe incorrectly and without adequate, critical reexam- 

 ination of material obtained under critical conditions. 



NOMENCLATURE 



Amoeba muris was originally described by Grassi (1881) from 

 rats and mice, but only in the motile stages. His account aifords 

 no basis for distinguishing between the two forms Kessel (1923a) 

 has found in rats and mice. However, Wenyon 's (1907) figures and 

 account of the cysts of the amoeba which he designates as Amoeba 

 muris are sufficiently detailed to afford a basis for the specific recog- 

 nition of one of the two species. He described but one species in 

 the mouse and gives no account of the amoebae of the rat. His 

 account apparently applies wholly, or in the main, to one species, 

 but in his plates there are at least three figures of cysts (his pi. 10, 

 figs. 20, 33, 34) which clearly differ in nuclear structure from the 

 others delineated by him. He makes no reference to these differences 

 in his text or in his diagram of Amoeba muris. His references to 

 the figures do not deal with any of the distinctive features of these 

 three cysts, namely, the peripheral chromatin blobs which characterize 

 the nucleus of Councilmanin dectimani (Rudovsky). 



We conclude, therefore, that Wenyon 's paper (1907) deals pri- 

 marily with the species muris and thus emends Grassi 's account and 

 sufficiently establishes its characteristics, to wit, budding in the cysts 

 and the absence of large chromatin blobs of peripheral chromatin on 

 the nuclear membrane in the cysts. The budding process, the often 

 faint nuclear membrane, and the diffused karyosome which char- 

 acterize Councilmania are recognizable in his figures, though not 

 always portrayed with accuracy of detail, especially the numerous 

 prophases of mitosis. We believe that three of his figures (his pi. 10, 



