OSTEOLOGY OF SCOMBROID FISHES 



RELATIONSHIP TO THE SCOMBROID FISHES. 



That Leiognathus belongs with the scombroid fishes there can be lit- 

 tle doubt. Its external characters and general appearance, which must 

 be considered, point to such a relationship to the extent, in fact, that 

 it has often been considered as a member of the family Carangidae. On 

 the other hand it does not resemble in any way the percoid fishes. 



It is not, however, a member of the family Carangidae, nor is it 

 probably very closely related to it. The gill-membranes are connected 

 with the isthmus in Leiognathus. In the family Carangidas they are free 

 from the isthmus. The suborbital chain is incomplete. In the Carangi- 

 dae it is complete. The supraoccipital crest does not extend forward. In 

 the Carangidae it is carried forward by the frontals for the entire length 

 of the cranium. The alisphenoids are in contact. In the Carangidae they 

 are separate. Leiognathus differs further from the members of the 

 Carangidae in the peculiar attachment of the hyoid arch to the lateral 

 head bones; in the pelvic arch being deep, and in the very protractile 

 premaxillaries. 



Where its relationship lies among the scombroid fishes is more diffi- 

 cult to say. It is probably an abbarrent family like so many others in 

 that relationship. The character of its supraoccipital crest, and its deep 

 pelvic girdle may indicate a connection with the scombroid stem near 

 place where the Chaetodontoid fishes branched off. 



