496 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 87 



ZELLERIELLA CORNIOLA Carini 



Figure 51 



Host: Leptodadylus ocellatus (Linnaeus), from Brazil. 



The body is slightly flattened, long, and curved. This species 

 measures 70^90/x in length, and the anterior end is the region of 

 greatest width. From there, the animal gradually decreases in width 

 toward the posterior end, which is pointed, and in some specimens 

 twisted. Two nuclei, 8-10^ in diameter, are located about Sju from 

 each other in the anterior half of the body, 



ZELLERIELLA FALCATA Carini 



Figure 52 



Host: Engystoma ovale Schneider, from Brazil. 

 This species of Zelleriella found in Sao Paulo is very much flattened 

 and often presents a certain degree of twisting. It has a rather 



FiGUEE 52.— Zelleriella falcata Carini from Engystoma ovale. No magnification given. (After Carini.) 



variable form, sometimes spindle-shaped, sometimes cone-shaped; 

 however, the form that has been observed most frequently and that 

 appears to be the most typical is that of a comma, more or less elon- 

 gated. The anterior end is large and obtuse, the posterior end slender. 



The size is highly variable. The small forms are often fusiform and 

 measure nearly 50-1 00/x in length and 20-30/i in width. The well-de- 

 veloped individuals, with the characteristic form of a comma, measure 

 200-300m in length and 40-80^ in width. 



The two spherical nuclei, about IS-lTju in diameter, are found at 

 the anterior part of the animal. Each nucleus has nucleolar substance 

 in the form of small irregular blocks. The two nuclei are situated 

 obliquely to the axis of the body. The distance between the two 

 nuclei is about 20-25/x. 



