ACANTHOPTERYGII 



703 



Beiycidae ; and the resemblance which their terminal forms bear 

 to the Anacanthini is, as pointed out by Regan, probably to be 

 ascribed to convergence, not to any close genetic affinity, as 

 hitherto believed by many authors. 



pta- 



pelv 



ptcl 



FIG. 427. Pectoral arch and pelvis (left side) of A, Trachinus draco; B, Percophis 

 brasilianus ; cl, clavicle ; cor, coracoid ; pelv, pelvis ; pt, pterygials ; ptcl, post- 

 clavicle ; pte, post-temporal ; sc, scapula ; scl, supraclavicle. 



The character of the position of the scapular foramen, either 

 in the scapular bone or between it and the coracoid, which 

 obtains in many genera of this division as well as in most of the 

 Anacanthini, has proved to be unreliable even for the purpose 

 of family definition ; it is, however, of assistance in determining 

 the relation of certain obscure, degraded forms placed by some 

 authors with the Anacanthines, by others with the Blenniids. 



SYNOPSIS OF THE FAMILIES. 



I. Pectoral rays attached to the scapula and to a series of pterygials of 

 which only one or two are in contact with the scapula (see Fig. 427) ; ventral 

 fins jugular, with 1 spine and 4 or 5 soft rays ; anterior dorsal rays usually 

 spinous or not articulated, often forming a detached fin. 



A. Epipleurals present. 



1. Second suborbital produced inwards to support the eye-ball. 

 Ventrals close together ; scales very small, cycloid, forming oblique bands 



1. Trachinidue. 

 Ventrals widely separated ..... 2. Percophiidae. 



2. No subocular shelf. 



Ventrals widely separated ; two nostrils on each side 3. Leptoscopidae. 

 Ventrals widely separated ; a single nostril on each side 



4. Nototheniidae. 



Ventrals close together ; scales very small, forming oblique bands ; head 

 partly covered with bony plates ... 5. Uranoscopidae. 



