176 ELOPIFORM FISHES 



The quadrate is fan-shaped. The posterior or ventral margin lies almost hori- 

 zontally, with the expanded condyle directed antero-ventrally. A groove on the 

 medial surface of the quadrate received the lower end of the symplectic. 



The postero-ventrally inclined limb of the ectopterygoid fits tightly around the 

 anterior border of the quadrate. The longer antero-dorsally inclined limb runs 

 along the entire length of the endopterygoid. A shallow crest of bone arises from 

 the dorsal margin of the ectopterygoid at the angle in the bone. This crest is similar 

 to that developed in Osmeroides latifrons and homologous with the peculiarly shaped 

 ectopterygoid process of Recent albuloids. The endopterygoid is oval, at least three 

 times as long as wide. The convex buccal surface bears a large patch of teeth of the 

 same form but of smaller average size than those borne by the parasphenoid. The 

 anterior limit of both endopterygoid and ectopterygoid is difficult to decipher in 

 any specimen as this region is covered by the crushed remains of a spongy ossification 

 representing a weakly ossified autopalatine. The autopalatine of Recent albulids is 

 only weakly ossified in large individuals. The anterior end of the autopalatine in 

 Lebonichthys is represented by a rounded knob formed of more compact bone than 

 that posteriorly. The palatine head articulates with the mesethmoid medially and 

 the inner face of the maxillary head anteriorly. B.M.N.H. P. 4855 shows a small 

 patch of palatine teeth which are villiform in shape, not needle-like as in Albula. 



Dermal upper jaw. Those specimens exhibiting a premaxilla indicate that there 

 was a very close union between this element and the ethmoid. The premaxilla is 

 broad anteriorly where it meets its partner in the mid-line. Posteriorly the alveolar 

 portion is tapered. The lateral surface of the premaxilla is marked by two or three 

 pores but interconnecting canals cannot be traced ; thus the presence of a premaxil- 

 lary sensory canal is known by inference rather than from direct evidence. A narrow 

 band of fine, needle-like premaxillary teeth is found along the slightly convex oral 

 border. 



Unlike the premaxilla, the maxilla is often found dissociated from the neuro- 

 cranium. Anteriorly the expanded head of the maxilla turns dorsally and medially. 

 Posteriorly the maxilla expands into a shallow ovoid which is overlain postero- 

 dorsally by a single elongate supramaxilla. The maxilla is grooved dorsally behind 

 the maxillary head and ventrally beneath the head. The dorsal groove marks the 

 position occupied by the overlying first infraorbital. The ventral groove contained 

 the alveolar portion of the premaxilla. The maxilla is edentulous. 



Mandible. The mandible is short and bears a prominent coronoid process deve- 

 loped towards the posterior end of the jaw. The dentary symphysis is turned 

 slightly ventrally. Distinctive albuloid features of the mandible are the inflected 

 ventral margin and the presence of a deep groove containing the mandibular sensory 

 canal. The mandibular sensory canal was not covered by bone ventrally. The 

 dentary bears a band of needle-like teeth along the oral margin. Posteriorly the 

 articular forms the articulatory cup. The medial surface of the mandible bears a 

 large endosteal articular and sesamoid bone. 



Hyoid arch, branchiostegal rays, gular plate and gill arches. The ceratohyal is, as 

 usual in teleosts, ossified in two sections, a large anterior and small posterior element. 

 The former is represented by a thick bone which is constricted in the anterior third. 



