THE OPALINID CILIATE INFUSORIANS. 



101 



sometimes ellipsoid, but much more usually somewhat pear-shaped. 

 These nuclei are resting in a highly reticulate late metaphase. The 

 endospherules are large in this species. 



ZELLERIELLA [BOULENGERI], new species (?). 



A specimen of this form has been deposited with the United States 

 National Museum as Cat. No. 16472. 



Fig. G8. — Zkllekiella [boulbngebi], X 460 diametees. 



Host. — Prostherayis houlengeri Barbour, one infection in United 

 States National Museum specimen No. 52406, 22 mm. long, from 

 Gorgona Island, Colombia, South America. 



Measurements: A^of a small individual; B^ of one of medium size; 

 C, of the largest one observed — 



Measurements. 



Length of body 0. 057 



Width of body 028 



Thickness of body 



Length of nucleus 



Width of nucleus 



Cilia line interval: 



Anterior 



Posterior 



.0145 

 ,0087 

 .0087 



0.063 

 .047 

 .0155 

 .0087 

 .0054 



, 00187 

 .003 



0.111 

 .047 



This Zelleriella seems very similar to Z. atelopyxena [stelsneril^ 

 but its nuclei are spherical in almost all individuals, instead of ellip- 

 soidal. They seem to be resting in a late metaphase, entering upon 

 the reticulate condition, but the preservation is not good enough to 

 allow very clear vision of the cytological phenomena. 



