GENUS ENDOLIMAX 239 



nuclear membrane which appears to be free from chromatin, all of which 

 seems to. be concentrated in the karyosome. The latter varies very much 

 in shape, and may consist of an aggregation of several distinct granules. 

 There may be a single angular or irregular mass more or less central in 

 position; or lying against the nuclear membrane on one side there may 

 be a large mass connected by a fibre with a smaller mass at the opposite 

 side. In other nuclei a single large mass may be connected with two or 



• ••• 



/# 



^ 



\i 



Fig. 111. — Endolimax nana ( x 3,000). (Original.) 



1-3. Vegetative forms. 4. Vegetative forms parasitized by Spliasn'ia. 



5-6. Uninucleated cysts, one with glycogenic vacuole. 7. Cyst with two nuclei. 



8. Cyst with two nuclei in division. 9-12. Cysts with four nuclei. 



more smaller granules. The karyosome in its typical form is not a 

 spherical body, like the karyosomes of the small amoebae (HartmanneUa), 

 which frequently develop in old material from cysts which have passed 

 through the intestine. It is the marked irregularity in the shape and 

 structure of the karyosome which is such a characteristic feature of 

 E. nana, and enables it to be distinguished from the small forms of E. his- 

 tolytica (Fig. 95, lo and ii). 



The cyst of E. nana was first figured by the writer (1915e), who then 

 thought it might be a cyst of Chilomastix mesyiili. This error was sub- 



