486 PROCEEDINGS OF THE NATIONAL, MUSEUM vol.87 



Two individuals were found broader than long and with four nuclei 

 in a line across the much widened body. I interpret this as due to 

 the delay of one longitudinal division. A much-elongated individual 

 with 10 circular nuclei I interpret as due to repeated nuclear division 

 without fission. The direction of the rows of cilia in this specimen is 

 nearly transverse to the greatest length of the body. The condition 

 is still more abnormal than that shown in the 4-nucleated forms, 

 more than two morphologically longitudinal fissions having been 

 omitted and the "width" having become greatly overdeveloped. 

 The host of these Zelleriellas had been kept in captivity for about 10 

 days before its parasites were studied. 



ZELLERIELLA URUGUAYENSIS QUADBATA. new forma 



FiGUBE 41 



Type: U.S.N.M. No. 22628. 

 Host: Bujo dorbignyi Dum^ril and Bibron. 



In this host from Rio de Janeiro, and perhaps also from Monte- 

 video (records confused), are many infections containing individuals 



FiGUEE Al.—Zelleriella uruguayensis quadrata, new forma, from a tadpole otBufo dorbignyi, X 750. 



shaped like and as large as small Z. uruguayensis, and they have as 

 large nuclei; among these are other individuals having a more or less 

 truncate posterior end. Comparison with undeveloped Z. antunesi, 

 to be described, from tadpoles of Bufo crucifer suggests that the broadly 

 truncate condition is due to what is really an undeveloped point or 

 rudimentary tail at one posterior angle, the other being rounded. In 

 some individuals the posterior end appears split, the nascent point 



