532 R. L. Mooclie — Fossil Frogs of North America. 



believe them accurate so far as they go, must be confirmed and 

 extended. If the metameric arrangements of the primitive 

 ossification rings in the urostyle indicate that the Salientia 

 came from ancestors with long vertebral columns, then Pelion 

 lyelli from the Carboniferous of Linton, Ohio, may well stand 

 in such an ancestral relation. The species is, however, very 

 little known. The remains were the first discovered in the 

 Linton beds of Ohio and in spite of careful search and among 

 the hundreds of other specimens taken from this interesting 

 locality, there has not turned up a single fragment that 

 resembles Pelion lyelli. Whether the Linton fauna will be 

 rediscovered remains to be seen. 



The remains of Pelion lyelli consist of the impression of 

 the ventral surface of the skull and mandible highly carbonized 

 and the structures obscured ; a portion of the vertebral column ; 

 the major portion of the pectoral girdle and arms ; remains of 

 one leg ; and an indication of the pelvis. 80 far as the form 

 of these elements go they are all strikingly salientian, as was 

 noticed by Wyman and Cope and to which attention has been 

 several times called. 



It would be too bold a statement to say that Pelion is an 

 ancestral salientian, for our knowledge is such that we can say 

 but little more than that Pelion looks like a frog with a char- 

 acteristic long leg and a long back. 



The specimen of Pelion lyelli is in the American Museum 

 of Natural History. 



The history of the Salientia geologically is an interrupted 

 one and if Pelion is a frog then the next indication we find of 

 frogs in America is in the Upper Jurassic (Comanchean), in 

 the Como Beds of Wyoming first mentioned by Professor 

 Marsh in 1887 and more fully described by the writer in 1912. 



EOBATRACHUS AGILIS Marsh. 



Marsh, this Journal (3), xxxiii, p. 328, 1887. 



Marsh, Proc. Brit. Assoc. Science, Aberdeen Meeting, 1885, p. 1033. 



Marsh, Monograph U. S. G. S., xxvii, p. 508, 1897. 



Moodie, this Journal, xxxiv, p. 286, 1912. 



The specimens of Fobatrachus agilis Marsh seem to indicate 

 a bufonid nature for the species. In fact I think we would be 

 safe in locating the species in the family Bufonidre. The 

 reasons for placing the species in this family are chiefly on 

 account of the well-developed condition of the lower end of 

 the humerus (fig. 1, a\ 2, d\ and its apparently calcified con- 

 dition. The ulno-radial articular surface of the humerus is 

 certainly not the same in Fobatrachus agilis as it is in Rana 

 pipiens or Rana cat esbiana, and it does resemble the epiphysial 

 structures of calcified cartilage of some of the toads. 



