498 



FISHES. 



hyoid bones beneath. The hyomandibular and its inferior 

 segment the symplectic connect the quadrate with the side 

 of the skull. Of the six hyal bones, the largest and most 

 important is the ceratohyal, which bears seven long branchio- 

 stegal rays. 



The toothed premaxilla forms the upper part of the gape, 



Fir,. 167. — Disarticulated sl-cull of Cod. (From Edinburgti 

 Museum of Science and Art. ) 



S.O., Supra-occipital ; Pa., parietal ; Fr., frontal ; .If.E., meseth- 

 moid ; A'., nasal; P.E., parethmoid ; Ot., otics ; E.G., ex-occi- 

 pital; B.C., basi-occipital ; Pa.S., parasphenoid ; J'., vomer: L., 

 lachrymal; orl>., orbitals ; /f.Jil., hyomandibular; .^■., symplectic ; 

 Q., quadrate; Pf., pterygoid; int.pt., metapterygoid ; ins.pt., 

 mesopterygoid ; PI., palatine; I\[x., ma.\illa ; Pjny., prem.a.\lUa ; 

 Ar., articular; An., angular; D., dentary ; ii.h., urohyal ; h.h., 

 hypohyal ; c.Ji., ceratohyal; cp.h., epihyal ; ill., imer-hyal; Op., 

 opercular: S.op., sub-opercular ; /'.('/., inter-opercular ; /.ci/., pr^e- 

 opercular. 



while the maxilla which articulates dorsally with the vomer, 

 and nearly reaches the quadrate posteriori)', does not enter 

 into the gape. Both are membrane bones. 



In the opercular fold are four membrane bones. 



