532 



PISCES FISHES. 



((') Along the floor : basi-occipital, parasphenoid, voiners. 



(c/) Around the ear on each side : sphenotic, pterotic, and epiotic 



(above), prootic and opisthotic (beneath). 

 (<.') In front of and around the orbit : parethmoid, lachrymal, 



orbitals. 



Thus the haddock's skull shows in two respects an ad- 



Fr 



5.0. 



M.E. 



op. 



FIG. 260. Disarticulated skull of cod. From Edinburgh 

 Museum of Science and Art. 



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

 moid ; A 7 ., nasal ; P.E., parethmoid ; Ot., otics ; E.O.. ex-occi- 

 pital ; B.O., basi-occipital ; Pa.S., parasphenoid ; I 7 . , vomer ; 

 L., lachrymal; orb., orbitals ; H.Af., hyomandibular ; S., 

 symplectic ; Q., quadrate ; P/., pterygoid ; ntt.pt., metaptery- 

 goid ; ins.pt., mesopterygoid ; /*/., palatine; J/.r., maxilla; 

 Piny. , premaxilla ; A r., articular ; A ., angular ; Z>.,dentary; 

 u.h., urohyal ; k.h., hypohyal ; c.h. , ceratohyal ; ep.h., epihyal ; 

 /.//., interhyal ; Op., opercular ; S.op., sub-opercular ; i.op., 

 inter-opercular ; p. op., prai-opercular. 



vance upon that of the skate : first, in the ossification of the 

 primitive cartilage ; and second, in the addition of membrane 

 bones. Of the latter, the parietals and frontals cover over 

 the spaces which in the skate form the fontanelles. 



