584 CLASSIFICATION OF THE MAIL-CHEEKED FISHES. 



Interclavicles have been attributed to the Coitidce, by Professor i 

 Parker. 



The post-temporals are firmly co-ossified with the cranium in at least i 

 tbe Trujlidw, Pcristedn<hv, and Dactylopteridce, and to such an extent 

 that it is very difficult to trace the line of union between them, the sutures 

 being less distinct than those between others of the normal bones of the 

 cranium. 



The "basal pectoral radii" or actinosts are much enlarged in the j 

 Hemitrtpteridae and Gottidce, whereof a portion are joiued directly to the] 

 proscapula and widely separate the hypercoracoid and hypocoracoid. 



The inter operculum is entirely separate from the other opercular 

 bones in the Peristediids and Dactylopterids. In the Peristediids they 

 are elongated and blade-like laminar bones, but in the Dactylopterids 

 they are atrophied and reduced to osselets under the extended anterior 

 portion of the preoperculum just behind the lower jaw. 



The muscular tube whose presence or absence determines the position 

 in Professor Cope's system of various forms is present in all of the 

 typical mail cheeked fishes except the Hemitripteridce and Dactylop- 

 teridce, but in the former it is replaced by a modified device, while in the 

 latter it is wholly wanting; it is as well developed in the Cottids. referred 

 by Cope to the Scyphobranchii as in the Triglids and Peristediids placed 

 by him among the Distegi. 



It is indeed more than probable that the real reason which influenced 

 Professor Cope to segregate the mail-cheeked fishes as he did was not: 

 the presence or absence of the myodome, but the development of two or 

 four epipharyugeals. 



The number of epipharyngeal, however, is not co-ordinate with the 

 development or atrophy of the myodome, as may perhaps have been 

 assumed. In this connection, too, it may be explained that the rudi- 

 mentary and edentulous epipharyugeals have been counted by Pro-' 

 fessor Cope as well as the dentigerous ones. There is only one pair of 

 dentigerous epipharyugeals in the Cottids and Hemitripterids, and there 

 are three in the typical Scorpaenids, Triglids, and related forms. But 

 in forms otherwise closely agreeing with the typical Scorpcvnidcv in oste- 

 ological characters — the Apistinw — there are only single epipharyugeals, 

 as in the Cottids. We are consequently led to the conclusion that 

 the development or non-development of a myodome and the number 

 of epipharyugeals are of less systematic importance than Professor Cope 

 (quite naturally) inferred. 



If the deviations from the diagnoses of Professor Cope have been 

 thus detailed, it is not in the line of criticism, but because that accom- 

 plished zoologist has so well studied the osteological characteristics of 

 the fishes. The uniformity in respect to the parts commented upon is 

 so great in most of the forms belonging to the groups diagnosed that it 

 has impressed him, perhaps unduly, and, by the contrast, the wide and 



