GREGORY: FISH SKULLS 



255 



wrasses in having strong pharyngeal teeth; but the opposite lower pharyngeals are not 

 coalesced, merely attached by their inner edges or united by suture (Tate Regan, 1913a, 

 p. 130); the ascending processes of the premaxillae are often, but not always, very long, 

 extending over the roof of the skull to the occiput, this arrangement implying that the 

 mouth is strongly protractile. This is well shown in the figure of the skull of Petenia splen- 

 dida given by Regan (1924, p. 206, Fig. \2A). Regan notes {op. cit.) that the fins are 

 usually as in the Serranidae and other generalized Perciformes. 



na 



■■•. pf & parefh 



Tautogolobi-us adspersus 



Fig. 129. Tautogolabrus adspersus. 



According to Frost (\927b, p. 302), the otolith (sagitta) of Talapia zillii of the family 

 Cichlidae resembles that of Perca in basic features. This family is classed by Tate Regan 

 in the Perciformes division of the Percomorphi. 



Pomacentrids. — The pomacentrids are mostly small-mouthed, deep-bodied percoid 

 fishes that have the lower pharyngeal bones united and tooth-bearing and are in certain 

 characters like the wrasses but differ widely from the latter in the vertebral column and rib 

 attachments. Tate Regan (1913a, p. 131) therefore assigns them to a separate division of 

 the Percoidea, named Pomacentriformes, next to the Labriformes. The two pomacentrid 

 skulls here figured (Figs. 127, 128) show very small mouths of the nibbling type, the solidly- 

 built jaws packed with close-set minute teeth. The position of the quadrate-articular joint 

 in Microspathodon is remarkably far forward in front of the anterior border of the orbit; but 

 on account of the downward prolongation of the snout and the mouth, and of the raising of 

 the quadrate joint, the mouth points forward instead of upward. The rest of the skull 

 conforms to the short steep type already seen in other families. Frost (1928a, p. 451) notes 



