THE OPALINID CiLIATE INFUSOEIANS. 235 



The characteristic feature is that the sharply pointed posterior 

 end is bent to one side (to the same side toward which the morpho- 

 logical anterior end is bent). Opalina japonica shows a similar 

 condition, but much less developed. In this connection compare 

 Opalina [larvarum], page 244. 



OPALINA DRAYTONII, new species. 



Type. — United States National Museum Cat. No. 16600. 



Host. — Bana draytonii Baird and Girard, many living infections 

 from frogs purchased in San Francisco, California (locality of col- 

 lection doubtful), April, 1913. The type infection is from one of 

 these frogs. Also two infections in United States National Museum 



Fig. 209. — Opalina coracoidea, x 425 diameters. (After Bezzenberger.) 



specimens from San Pedro Mountain, Lower California (Mexico), 

 and one from another National Museum specimen from San Fran- 

 cisco. 



Measurements of an average individual. — -Length of body 0.17 mm. ; 

 width of body 0.12 mm.; thickness of body, anterior 0.012 mm., 

 middle 0.015 mm., posterior 0.015 mm.; diameter of nucleus 0.004 

 mm. to 0.0063 mm. ; cilia line interval, anterior 0.002 mm., posterior 

 0.004 mm. 



Most individuals from these infections are very broad, others are 

 more slender. The slender forms often, and the broader forms occa- 

 sionally, show an indication of an abrupt posterior point, which 

 however, is not acute as in O. japonica, 0. coracoidea, and O. \lar- 

 varurn], but is itself rounded. The condition is very different from 

 0. ranarvmi. The nuclei, like those of O. japonica, run smaller 



