GREGORY: FISH SKULLS 



261 



Percesoces (Barracudas, Silversides, Gray Mullets) 



This group, the Percesoces of older authors and the Mugiloidea of Regan, even when 

 restricted to the following three families, includes such diverse-rlooking fishes as the minute, 

 small-mouthed silversides (Atherinidae), the round-headed grey mullets (Mugilids) and 



6ca/edone 



.■supclt 



T^lenoid ^'^''' 



■facf 



irs/ol 



Cirrhitus rivulatus 



Fig. 135. Cirrhitus rivulatus. 



the fierce pike-like barracudas (Sphyrsenidae). The researches of Starks (189%), Jordan 

 and Hubbs (1919), besides those of earlier authors, leave no doubt that the group is a 

 natural one within the percomorph series, but the related problems as to what were the 

 characters of the ancestral group from which the present families have become diversely 

 specialized, and what was the derivation and exact relationship of that group, are still 

 debatable. The group is in some way connected with the Percomorphi, with which it 

 agrees in fundamental skull structure, in the presence of a spinous dorsal fin and in the 

 possession of one spine and five soft rays in each pelvic fin. Even the otoliths of the 

 Mugilidx and Sphyraenidse, as described by Frost (1929a, pp. 120-129), resemble generally 

 the serranid and percid types. 



The presumption is then that, as Dollo (1909) has suggested, the subabdominal 

 position of the ventral fins in Sphyrcena is a secondary convergence toward the isospondyl 

 type rather than a direct inheritance. This inference is supported by the following facts: 



