GREGORY: FISH SKULLS 



277 



(3) The opercular is smooth, thin and covered with silver pigment; the preopercular 

 has a smooth border. 



(4) The subocular shelf is absent. 



(5) The first vertebra is closely appressed to the occiput. 

 No special resemblances to the chaetodonts were noted. 



The otolith (sagitta) of Psettus argenteus of the family Scorpididae, according to Frost 

 (1927^, p. 304), resembles those of Perca and Centropomus, except in details. The sagitta 

 of Ephippus faber, according to Frost {1927b, p. 304), is very peculiar, but resembles that 

 of the young form of Mullus except in details. This resemblance is so striking that it 

 would not be surprising if it gave a clue to the origin of the scorpidid-chaetodont series 

 from the perciform stock near the haemulid-sparid-muUid branch. 



Angelichthys ciliaris. 



Platax. — This fish (No. 462, Brit. Mus. Nat. Hist.) of the family Ephippidae is definitely 

 advanced beyond that of Scorpis in the general direction of the angel-fishes and chaetodonts. 

 Its skull (Fig. 151) is an immediate structural ancestor to that of Ephippus {Chatodipterus) . 



