466 BULLETIN 120; UNITED STATES NATIONAL MUSEUM. 



P. regularis (Gold Coast, "British East Africa"). 



P. stevensoni (Sudan). 



P. xenopodos (Belgian Congo), 



Zelleriellae, none. 



Cepedeae madagascarietisis [of HyperoUus] (West Africa). 



C. magna (The Cameroons). 



C. plirynomanUdis ("British East Africa"). 



Opalina camerunensis (The Cameroons). 



0. natalensis (Sudan). 



O. species ?, from Rana mascareniensis (Gold Coast). 



2, MADAGASCAR, SEYCHELLES ISLANDS, CEYLON. 



Protoopalinae, none. 



Zelleriellae, none. 



Cepedea madaga'Scariensis (Madagascar). 



C. eeychellensis (Seychelles Islands). 



Opalma virgula (Ceylon). 



From these lists we see that northeastern North America has 

 Opalinids only of the genus Opalina, and that the same is true of 

 southeastern United States except for probably a single species each 

 of the genera Zelleriella and Cepedea. Zelleriella scaphiopodos of 

 North Carolina is probably an immigrant from Central America by 

 way of the Gulf coast. Cepedea floridensis from Key West, Florida, 

 doubtless also came from Central America, either by way of the Gulf 

 coast or from the Greater Antilles. The southern tip of Florida 

 shows many close f aunal affinities with the West Indies and Central 

 America. The eastern North American Opalinae all belong to the 

 Opalinae angustae. 



The region of the north coast of the Gulf of Mexico is not distinct 

 in its Opalinid fauna. Its sole Zelleriella doubtless came from Cen- 

 tral America. Its two Opalinae are forms with chiefly eastern dis- 

 tribution. 



The great grassy plains also are not well demarcated in their 

 Opalinid fauna. Their only Protoopalina belongs to the exclusively 

 North American subgenus resident in Scaphiopus, this particular 

 species (mifotica), however, having adopted the Urodele host Am- 

 hystoma tigrinum. The Opalinae are of the characteristic American 

 subgenus Opalinae angustae and two of them are of very wide range, 

 one being spread from Massachusetts to Mexico and the other rang- 

 ing to the north and west to the regions of such extreme cold that 

 Anura can spread no further. 



The Rocky Mountain region gives us two Protoopalinae of the 

 subgeneric group characteristic of Scaphiopits, and a single Zelleri- 

 ella from Utah which might about as well be assigned to the Sonoran 

 region. It is evidently an immigrant from the south. There is also 

 one Opalina, found also in Costa Rica. 



The Sonoran region, comprising the semidesert territory of south- 

 western United States and northern Mexico, has representatives of 



