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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 87 



have been not later than the early Cretaceous, if not in the Jurassic 

 period. Migration from eastern Asia by way of the Cretaceous 

 circum-Pacific land-strip, which Arldt (1907), Scharff (1911), and 

 others think extended well to the south on both the Asian and Ameri- 

 can ends, is equally a possibility, but there are no eastern Asian or 

 western North American species today to lend support to this hy- 

 pothesis. 



The opalinids of the gastrophrynids are: Protoopalina (North and 

 South America, Africa, India, Philippine Islands), Zelleriella (Central 



Figure 154. — Geographic distribution of the Gastrophrynidae. 



America, southern South America), Cepedea (Cochinchina), Opalinae 

 latae (India), Opalinae angustae (southeastern United States, adopted 

 after the middle Pliocene from Hylas directly or indirectly). I do not 

 see that they give evidence as to the place and time of origin of their 

 hosts. 



THE RANIDAE (Pig. 155) 



This is a large family of many genera, found abundantly in all 

 lands with suitable climate, except Australia, Tasmania, New Zea- 

 land, and South America. Australia has one Rana in the extreme 

 north, and South America has one Rana and two other genera of 

 Raninae represented in the northernmost regions. The family is a 

 dominant one and Rana, wherever the family is well represented, is 

 its chief genus. 



The opalinid parasites of the family are: Protoopalina (tropical and 

 southern Africa and Malay islands), Zelleriella (rare), Cepedea, and 

 Opalina. Zelleriella is a guest recently adopted by one Californian 

 Rana. It is also borne by Prostherapis and Phyllobates on the northern- 



