THE OPALINID CILIATE INFUSORTANS. 425 



exceptions, bear narrow Opalinas. The exceptions are Rann dray- 

 tonii of California (bearing Opalina draytonii) and R. copei and 

 R. pretiosa of Costa Rica and of Montana respectively (bearing the 

 rather broad form O. copel). Species of other genera of Raninae 

 bearing Opalinae- are Hylavibates rufus of "West Africa (bearing 

 O. eatnerunensis) ^ Phrynobatra^hus natcdenHs of the Sudan (bear- 

 ing 0. natalensis) and Polypedatcs macidatus of Ceylon (bearing 

 0. virgula^ a narrow form which, however, seems not to belong to 

 the same group as the narrow Opalinae from the Western Hemi- 

 sphere) . 



We thus see that the Raninae bear 6 species of Protoopalina^ 3 

 species of Zelleriella, 18 species and subspecies of Cepedea, and 19 

 species and subspecies of Opalina. The multinucleated Cepedeas and 

 Opalinas are therefore the characteristic Opalinids of the Raninae. 



I have had for study two species of one of the three genera of the 

 subfamily Dendrohatinue. These are Dendrohates tinctorius and 

 D. typographus^ both from Central America and both bearing Zel- 

 lerieUa dendrobatidis. No material has been available of Mantella 

 from Madagascar, or of Cardioglossa from the French Congo. 



From this review the Ranidae are seen to bear all the genera and 

 subgenera of Opalinidae, though few species are infected with Zel- 

 lerieUa., apparently in part because few species of Ranidae live in 

 the region where Zelleriella occurs. They seem hospitable to any of 

 the Opalinidae except Zelleriella with which they come into contact 

 and they have proven able to adopt Zelleriella. 



There are three further inquiries we may answer from this list of 

 infection data: First, as to the frequency of infection of Anura by 

 Opalinids; second, as to the species of Anura which are known to 

 harbor more than one species of Opalinid; and third, as to the simul- 

 taneous infection of one individual Anuran by more than one species 

 of Opalinid. 



First. — How frequent are infections by Opalinidae in the several 

 species of Anura ? What proportion of the individuals are infected ? 

 The material from the United States National Museum can hardly 

 be used to answer this question, for it is not certain what specimens 

 were promptly preserved after capture and were put in alcohol. 

 Specimens left to die before being preserved, or even specimens kept 

 in captivity too long, may not show Opalinidae, though these may 

 have been present originally. Again, specimens preserved in for- 

 malin rarely show Opalinids. Not only the parasites but also the 

 epithelial lining of the rectum are generally degenerate in formalin 

 specimens. I shall not attempt to pick out from the list the data 

 from specimens apparently preserved in alcohol, because, at best, 

 one could not be certain of this, since in many instances specimens 

 83103—23 28 



