42 



THE PROTOZOA 



network, or of a homogeneous body of considerable size (Karyo- 

 somes). Several different types of nuclei may be distinguished; 

 some of the most important being: (i) The distributed nucleus, 



Fig. 14. — Types of nuclei. [A. Calcituba polymorpha Roboz, from Schaudinn ; B. Colpidium 

 colpoda, from a preparation ; C. Euglena viridis Ehr. from a preparation ; D, Tetramitus c/iilomo- 

 H*tx, n. sp. ; E. Noctiluca miliar is Stir., from a preparation.] 



A single karyosome (A) becomes vesicular, and ultimately gives rise to several daughter-karyo- 

 somes (so-called "fragmentation" Schaudinn). Several karyosomes in Noctiluca (E) hold the 

 chromatin, the rest of the nucleus is filled with " achromatic " granules. In Tetramitus chilomonas 

 (D) the chromatin is scattered throughout the cell; the lighter-colored body in the centre of the 

 cell is the homologue of the deeply stained central body in Euglena (C). 



