﻿47 



85 



c. sctilopar 

 styldh.VMl ; 



liisihl hyoid ;mc1i, fi 

 : t'pihyal ; ch: cerat(ih\ 

 for liynnietit : ** gi-<io\' 



nm llic cmlcr siile. si 

 il: Itjil. Inill- hvixiliyals 

 ■ r.ir liiaiu'hiiisl.-fials. 



the preoperculum is allaclied lo Ihe lower margin almost lo Ihe mandibular arti- 

 culation; from this on the outer side a longitudinal ridge runs almost the whole 

 length of the quadrate parallel to its lower edge and immediately above the margin 

 of the preoperculum. The short anterior margin, above the articulation tor the 

 under jaw, is attached al ils upper pari to the small ectopterygoid (ekl). Connected 

 with the posterior margin of the latter lies the long, thin and narrow enlopterygoid 

 (ept), almost completely covered externally by the upper margin of the quadrate; 

 as in Ainphisile the up])er margin of 

 the enlopterygoid is connectetl with st 



the vomer in under the projecting 

 margin of the nasal; posteriorly the 

 enlopterygoid joins on to the anterior 

 end of the metapterygoid (mt), the 

 upper end of which continues the 

 attachment to the beak by means of 

 a connection with the lower, outer 

 margin of the mesethmoid. The last 

 is ossified to a much greater extent 

 in Centriscus than in Amphisile. 



The palatine (pa) is narrow and slender, connected anteriorly with Die front 

 end of the vomer and also with the ectopterygoid and entopterygoid ; at its poster- 

 ior end it touches the anterior point of the nasal; the normal process which pro- 

 jects forward over the upper jaw is very distinct and relatively prominent. 



The preoperculum along its narrow ascending portion covers the outer 

 side of the hyomandibular from the articulating cup for the operculum; under 



the eye its anterior margin spreads 

 out somewhat and passes over into 

 the horizontal part; this is on the 

 whole fairly narrow and very long; 

 a toothed ridge along the ascending 

 portion is continued at a blunt angle 

 along the horizontal portion. 



All 3 bones of the gill-cover 

 are present; the operculum — as 

 already mentioned — has a toothed 

 ridge, which sends out a short branch backwards at the projection near the arti- 

 culation with the hyomandibular. The in teroperculum {io, fig. 27) is long and 

 thin, its posterior end broadened out slightly to a small plate on the inner side 

 of the sub operculum; it also extends along the inner side of the preoperculum 

 and quadrate, reaching distally to the end of the latter at the mandibular joint. 



Of the lateral line canals one is very distinct, arising in the frontal over 

 the posterior margin of the orbit and continuing above the nasal openings right 



c scolopaa 



Fig. 29. 

 I arcli, frnni thi 

 fixed the lisan 



Minor 

 ■lit lew 



c. Lette 

 riliyal. 



