THE OPALIXID CILIATE IXFUSOEIANS. 



187 



This subspecies, in my infections, has a much smaller propor- 

 tion of long slender individuals than are found in infections of the 

 species proper. Its nuclei are larger, especially in the smaller indi- 

 viduals. Its endospherules are much larger, and the intervals be- 

 tween the lines of cilia are narrower, though the latter is a feature of 

 little diagnostic value. 



Fig 156. — Opalina obtrigonoidea Americana, form eugosa, from Bufo americands, X 



250 DIAMETERS ; d, IS APPAEEXTLY AN ANTERIOR CELL FROM TRANSVERSE FISSION. 

 OPALINA OBTRIGONOIDEA AMERICANA, form RUGOSA. new forma. 



T^pe. — United States National Museum Cat. No. 16584. 



Host. — Bufo aviei^anus Holbrook, 12 living infections from 

 Kaleigh, North Carolina, June, 1915; H. H. and C. S. Brimley, col- 

 lectors. 



Freshly taken infections often show their individuals shorter and 

 broader than the usual Ofdlina ohtrigonoldea anier'icana and most 

 of them crenate and rujrose, as indicated in the figures. Such 



