60 



BIOLOGY OF THE PROTOZOA 



structures. After treatment with beef broth the body of Dileptus is 

 enormously distended due to the swelhng of these cytoendosomes 

 (Fig. 24). 



The centrally placed intranuclear body is generally described 

 under the name karyosome, a term which has been so widely used 

 by students of the Protozoa and for so many obviously different 

 structures that it is practically synonymous with endosome or 

 Binnenkorper. Thus Minchin describes it as a combination of chro- 

 matin and plastin; Doflein defines a karyosome as a centrally placed, 

 sharply outlined and constant constituent of the nucleus, which may 

 contain no chromatin or may be a combination of other substances 

 with chromatin and which divides during nuclear division, to form 



B 



'■^!i.\, — s 





Fig. 23. — ^4, Endamceha intestinalis; (e) endosome; (c) cortex of chromatin; B, 

 nucleus and "sphere" (s) of A''odiZ?^ca ww^tarts with multiple endosomes. (Original.) 



two corresponding daughter structures (Doflein, 1916, p. 22), 

 Hartmann's (1911) definition is more limited, a karyosome in his 

 use of the term being an endosome (Binnenkorper) containing a 

 centriole. Belar (1921) finds a "karyosome" in CJdamydophrys 

 minor which breaks up and disappears forming neither chromatin 

 nor kinetic elements. If we attempt to combine these different 

 views into a common definition we find that a karyosome may be 

 an intranuclear body which may consist of plastin alone; or kinetic 

 element alone; or chromatin together with plastin; or a combination 

 of chromatin with kinetic elements; or a combination of chromatin, 

 plastin, and kinetic elements. Such a definition obviously would 

 fail to specify any particularly nuclear structure and so far as its 



