586 CLASSIFICATION OF THE MAIL-CHEEKED FISHES. 



GENETIC RELATIONSHIPS. 



Iii view of the wide range of variation that has oeeu shown to be 

 manifested by the various members of the great group of mail-cheeked 

 lislies, it may be considered that it is not a natural group. In one sense 

 it is not. The differences are certainly sufficient to justify the segrega- 

 tion of its elements not only into a number of families, but into seven 

 superfamilies. Nevertheless the relations between the various members 

 are such as to indicate that they form a natural although much inter- 

 rupted series, and the genius of Cuvier is apparently justified by a 

 detailed examination of the anatomy. 



The most generalized of the mail-cheeked fishes appear to be the Scor- 

 pseuoidea; these have the general form of ordinary fishes, like the Ser- 

 ranids, Sparida, and numerous others. Osteology also corroborates the 

 nearer relationship of those forms to the normal acanthopterygian 

 fishes. If we look around among those normal forms for the nearest 

 relatives of the mail-cheeked fishes, in the present state of our knowl- 

 edge, we appear to at least approximate the truth iu claiming for thern 

 a nearer relationship with the Cirritids than any others. This view, how- 

 ever, is simply hypothetical and can not be considered to be established 

 until we become better acquainted with the anatomy of the various 

 members of the suborder Acauthopterygii. Which of the Scorpamoidea 

 are the most generalized is a more difficult question to answer. 



In some respects the Chirids, or Hexagrammids, appear to be more 

 generalized than the Scorpamids. They are less armed with spines 

 than .the other representatives of the great group of mail-cheeked fishes, 

 and, what is still more significant, the dichost or basi-spbenoid is more 

 developed and approaches in form that exemplified in the normal Acan- 

 thopterygians; nevertheless, the parietal bones converge towards the 

 front so as to almost, if not quite, touch over the front of the supra* 

 occipitine. The parasphenoid sends elongated processes upwards to 

 meet corresponding processes of the subtectals or orbito sphenoids. 

 Iu both of these characters they deviate from the Scorpamids and ap- 

 proach the Cottids. For this reason, therefore, they are placed after 

 the JScorpaiiids and before the Cottids. The comparatively slight value 

 of the approximation or separation of the parietals thus appears and 

 demonstrates that it is inadvisable to separate widely groups resembling 

 each other in so many characters because of such differences. 



An elongate spinous portion of the dorsal fin and an inversely short 

 rayed portion are developed iu the Heuiitripterids; nevertheless, those 

 fishes agree in most osteological as well as most external characters 

 with the Cottids; consequently theuunaturalness of removing them afar 

 from the Cottids and associating them with the Scorpamids, as well as 

 the slight value of the relative proportions of the spinous and rayed 

 portions of the dorsal fin, becomes evident. 



The osteological characters of the Platycephalids and Iloplichthyids 



