xvi 



The homologies of the elements of the shoulder girdle of the Dipnoi 

 appear then to be as follows : 



THE GIRDLE IN OTHER FISHES. 



Proceeding from the basis now obtained, a comparative examination of 

 other types of Fishes successively removed by their affinities from the 

 Lepidosirenids may be instituted. 



I. 



With the humerus of the Dipnoans, the element in the Polypterids 

 (single at the base but immediately divaricating, and with its limbs bor 

 dering an intervening cartilage which supports the pectoral and its basilar 

 ossicles) must be homologous. 



But it is evident that the external elements of the so-called carpus of 

 teleosteoid Ganoids are homologous with that element in Polypterids. 



Therefore, those eleme nts cannot be carpal, but must represent the 

 humerus. 



1 Gelenkstelle der Brustflosse am prirailren Schulterknorpel. Gegenbaur. 



2 Clavicula. Gegenbaur. 



3 Verbindungsstelle des beiderseitigen Schulterknorpels. Gegenbaur. 



Prof. Gegenbaur regards the median cartilage as a dismemberment of a common 

 cartilage, the upper division of which receives the pectoral limb, while the lower 

 unites with the corresponding dismemberment of the opposite side and forms the 

 median cartilage. 



4 The suture separating the &quot;coracoid&quot; into two portions has been observed by 

 Dr. Gunther, but he could &quot; not attach much importance to this division.&quot; 



