18 ELOPIFORM FISHES 



anterior border of the metapterygoid overlaps the endopterygoid, while the ventral 

 margin is in synchondral union with the quadrate. 



The quadrate bears a stout articulatory condyle which in adult fish lies vertically 

 beneath the head of the hyomandibular. The posterior margin of the quadrate 

 is thickened. Upon the medial surface of the quadrate a deep groove runs close 

 to the posterior margin and accommodates the ventral end of the stylif orm symplectic. 

 The dorsal end of the latter is united with the hyomandibular shaft by cartilage. 



The ectopterygoid is composed of two limbs, the posterior grooved to fit the 

 anterior margin of the quadrate and the longer anterior limb disposed more horizon- 

 tally. The dorsal edge of the ectopterygoid is thickened and to this thickening is 

 attached a tough fold of skin which inserts on the medial face of the overlying infra- 

 orbitals. Gosline (1965) pointed out that there was no ectopterygoid process in 

 Elops but the thickened ridge in E. hawaiensis may be considered as such a rudi- 

 mentary process. The oral surface of the ectopterygoid bears many small villiform 

 teeth. 



The convex oral surface of the endopterygoid is covered with many small villiform 

 teeth, continuous with those upon the ectopterygoid. 



There is a small dermal palatine (dermopalatine) but no ossified autopalatine. 

 The palatine cartilage overlaps the anterior ends of the ectopterygoid and endoptery- 

 goid posteriorly. Anteriorly the cartilage is slightly swollen and bears a facet upon 

 the dorso-medial surface which fits against the floor of the nasal capsule. The 

 ventro-lateral surface of the palatine cartilage articulates with the maxilla but there 

 is no special facet developed. The dermopalatine is represented by a tooth plate. 

 The teeth borne by this plate are continuous with those on the ectopterygoid and 

 endopterygoid but are more like those of the vomer in shape, being pointed and 

 recurved. 



Dermal upper jaw. The upper jaw extends from the tip of the snout to behind the 

 orbit. The relative length of the upper jaw increases slightly throughout life. The 

 premaxilla forms a little less than one-third of the convex oral margin. The pre- 

 maxilla is relatively shallow, the maximum depth being equal to less than one-quarter 

 of its length and situated towards the anterior end. From its point of maximum 

 depth the bone tapers in both directions. The oral surface of the premaxilla bears a 

 band of small teeth. Each tooth is conical and bears a pointed enamel cap, set at an 

 angle to the main axis of the tooth. Basally the tooth is set within a shallow socket. 



The maxilla is elongate and deepest posteriorly. Anteriorly the maxilla curves 

 both dorsally and medially to end in a simple rounded head which articulates directly 

 with the ethmoid. Behind the maxillary head the dorsal surface of the maxilla 

 bears a palatine process which articulates with the ventro-lateral aspect of the 

 palatine through a biconcave sliver of cartilage. The oral margin of the maxilla 

 bears a band of small teeth similar to those upon the premaxilla. Posteriorly 

 the tooth band extends on to the lateral surface of the bone. 



There are two supramaxillae. The anterior supramaxilla is produced anteriorly 

 as a spine. The posterior bone also bears an anterior spine which overlies part of 

 the anterior supramaxilla. Both supramaxillae are without strengthening ridges 

 and are relatively immobile, unlike these bones in clupeoids. 



