592 



PROCEEDINGS OF THE NATIONAL. MUSEUM 



VOL. 87 



between. The opalinids of the subfamily Discoglossinae are Proto- 

 opaUnas of subgenus II. (2) The Ascaphinae spread northeastward 

 and across to extreme northwestern North America by way of the 

 land-strip that in Cretaceous times stretched north from eastern Asia 



Lept oda otylldae 



( Protoopallna I, 



Zellerlella) 



Hylldae 

 ( Cepedea . Opallnag 

 anguatae ) 



\ 



Ranldas 

 ( Cepedaa . Opallnae 

 latae) 



Gastrophrjmldae ^ 

 ( Frotoopallna . ' 



\ 



\ Pelobatldae 

 \ ( Frotoopallna II, 

 ^ Hi, IV} 



\ I 



\^ 7 



V 



/ 

 / 

 / 



/ Bvfo 



I ( Cepedea t adopts 

 / anything It 

 / meets) 



\ V ' / 



\ \ » / 



\ \ I / / 



\ \ ' / / 



\ \ t / / 



Discoglossidae ^ \ ' ^ ^ 



( Frotoopallna II) ^\ \ ' / / 



Archalo 

 Bufonidae 



(opalinids insuf- 

 ficiently Imown) 



I 

 I 



I 

 Plpldae 



( Frotoopallna I) 



Figure 147.— Chart suggesting possible phylogeny of the Anura. 



and east and then south, bounding the northern Pacific Ocean (fig. 

 143, a). Although this land-strip in Tertiary times united with 

 North America (fig. 144, h) its discoglossids never passed farther east 

 onto the main part of the North American continent even when the 

 way opened, but they remained on the narrow land-strip, being already 

 decadent, having retired to the mountains and living in and near the 



