THE OPALINID CILIATE INFUSORIANS. 423 



already seen that the Hylidae are rehictant to accept the characteris- 

 tic Leptodactylid parasites, the Zelleriellas, though being in the same 

 region. We have also seen that the Leptodactylids are completely 

 resistant to infection by the Hylid parasites, the Cepedeas and 

 Opalinas, though they live in contact with them. 



But the Hylidae are not the only Anura in tropical and south tem- 

 perate America which carry multinucleated Opalinids. One Rana 

 (chrysoprasma) in Central America harbors Cepedea occadentalis 

 and two other Central American Ranae {copei and pipieris austri- 

 cola) bear OpaJhiae {copei and ohtrigonoidea austricola). The 

 Bufos also, from the same habitat, contain both Cepedeas and Opa- 

 linas. Bufo hae77iaf Ulcus, of Central America, bears Cepedea, and 

 this Bufo and its neighbor B. typhonius bear respectively an as yet 

 unnamed Opalina and O. panamensis. The Ranas have been almost 

 as unwilling to accept Zelleriellas from the Leptodactylids as the 

 latter have been to accept multinucleated Opalinids from the Ranas. 

 Only one Rana, so far as known, bears ZelleHella, while no Lepto- 

 dactylid is known to bear any member of the subfamily Opalininue. 

 But we must remember that few Ranas have come into contact with 

 ZelleHella. The Bufos, on the other hand, have been most hospitable 

 to the Leptodactylid Zelleriellas, adopting them freely, but the Lepto- 

 dactylids have refused to share with the Bufos their entertainment 

 of the multinucleated parasites. 



The Gastrophrynidae are well represented in tropical, south tem- 

 perate, and north temperate America, in tropical Asia and the East 

 Indies, on the African Continent, and are especially numerous in 

 genera in Madgascar. I have Opalinids from only 10 American, 

 1 African, and 1 Cochin China species. The parasites of southern 

 Asian and especially Madagascaran species should be thoroughly 

 studied. They will probably yield valuable evidence as to the re- 

 markable relations indicated between the Anura of these two regions. 

 Papuan species should also have their Opalinids studied for com- 

 parison with the parasites, on the one hand, of American Gastro- 

 phrynidae and, on the other hand, of East Indian species of this 

 family. I realize fully the inadequacy of the data here presented, 

 but have no fuller material available. Two species of Gastrophryne 

 from Texas and southern Mexico give two Protoopalinas of quite 

 a distinct group containing only the species ovoldea and xyster. The 

 latter is the species of Protoopalma which approaches nearest to 

 Zelleriella. The anterior portion of its body is flattened. Further 

 flattening affecting the rest of the body would produce a very good 

 ZeUeriella. Another Protoopalma of a different sort is found in 

 Rhinoderma darwinii from Chile. Four Central American Gas- 

 trophrynids of the genera Atelopus, Eypopachus, and Engystomops, 



