314 ©. CLIFFORD DOBELL. 
supposed to be the homologue of the metazoan centrosome. 
We thus have a conception of binuclearity which starts 
neither from the somato-gametic nuclear differentiation of 
infusoria (Goldschmidt), nor from a condition in which the 
cell contained two equivalent nuclei (Lauterborn) ; but it pre- 
supposes the primitive condition to have been a tropho-kinetic 
binuclearity. These views of Schaudinn have been much 
elaborated by Hartmann and Prowazek (’07),' who have 
pushed them to their extremest limit. According to these 
two writers, other protozoan cells are really binucleate in 
just the same way as the trypanosomes, the only difference 
being that we usually find the kinetonucleus boxed up—as a 
karyosome—inside the trophonucleus. The encased nucleus 
TExT-FIG. 24. 
Entameba tetragena Viereck. N. nucleus, inside which 
isa “ karyosome” witha “ centriole” and ‘a kind of nuclear 
membrane.’ This is supposed to represent an encased 
nucleus. F', ingested body. (After Hartmann and Prowazek, 
07.) 
assumes many different forms, and it is said in some cases 
actually to show all the morphological features (centriole, 
nuclear membrane,” etc.) of a free nucleus (text-fig. 24). 
This kinetic nucleus is said to be recognisable in a variety 
of Protozoa. It is represented by the Nebenk6rper of 
Parameeba, by the Centralkorn of Heliozoa, by the nucleolo- 
centrosome of Huglena, by the karyosome in coccidia, ete. 
It is even suggested that the encased nucleus is visible in a 
form like Amoeba limax (cf. Vahlkampf, ’04) but I cannot 
persuade myself that this is so—with the best will. 
1 They are also held apparently by Keysselitz (08) and others. 
2 HK. g.in Entameba buccalis and E. tetragena. 
