THE COAL MEASURES AMPHIBIA AND THE 

 CROSSOPTERYGIA 



DR. EOY L. MOODIE 

 Department of Anatomy, University op Illinois, Chicago 



It lias been assumed for many years that the crossop- 

 terygian ganoids are more nearly in the direct line of 

 descent of the amphibia than any other known group of 

 fishes. Recent work along this line adds considerable 

 evidence to support this assumption and it is fast becom- 

 ing accepted as practically proven that such was the line 

 of descent of this group of vertebrates. Watson (1), 

 Broom (2), Gregory (3-4), Pollard (5), Klaatsch (6), 

 Budgett (7), the writer (8), and others have added to- our 

 knowledge of this relationship, which is based on the 

 structure of the skull, the limbs and the mandible, so far 

 as these anatomical features are known. Our knowledge 

 of the osteology of neither group is satisfactory and it is 

 to be hoped that additional material will do much toward 

 a solution of this problem. 



It is our purpose here to state in a brief manner what 

 the Amphibia from the Coal Measures add toward the 

 solution of the problem of the derivation of the amphib- 

 ians from the crossopterygians. 



The fish characters of the larval stages of the Amphibia 

 have been often cited as evidence of this relationship. 

 Budgett (7) says: 



It has been admitted by the most competent paleontologists that the 

 structure of the dermal bones of the head and shoulder girdle of Poly- 

 pterus is so like that of certain Stegoccpliali, that it must be regarded 



development of the skeleton that distinctly approach the condition of 

 the Amphibia. The only possible interpretation of these facts appears 



recent forms, having some characters in common with most of the great 



The writer (8) has called attention to the similarity of 

 arrangement of the lateral line canals in Amphibia and 

 Crossopterygia and has attempted a correlation of the 

 cranial elements. In that essay it is stated : 

 637 



