60 ELOPIFORM FISHES 



The cleithrum is large and curves antero-ventrally. The anterior tip meets its 

 fellow in the mid-line. The anterior margin of the bone is thickened and dorsally 

 this thickening forms a short spine to which Baudelot's ligament is attached. A 

 horizontal ledge projects medially from the ventral part of the cleithrum. 



The endoskeletal girdle consists of the scapula, coracoid and mesocoracoid. The 

 scapula is of complex shape. Laterally it spreads over the medial face of the cleith- 

 rum. Medially, the horizontal portion of the scapula contacts the coracoid and meso- 

 coracoid through synchondral unions. The posterior margin of the scapula bears a 

 saddle-shaped depression receiving the first pectoral fin-ray. The scapular foramen 

 is incomplete. 



The coracoid is elongate and lies in the vertical plane. Posteriorly the lateral 

 face unites with the scapula through a simple synchondral join, and with the meso- 

 coracoid through an interdigitating synchondral join. The coracoid also exhibits 

 a syndesmotic union with the horizontal cleithral ledge. The posterior margin of 

 the coracoid is capped by cartilage. The medial face of the coracoid lies against 

 that of its partner while the anterior margin is bound by loose connective tissue to 

 the cleithrum. A large foramen pierces the coracoid below its union with the 

 scapula and mesocoracoid. The latter bone spreads over the inner surface of the 

 cleithrum. A narrow mesocoracoid arch passes ventro-medially to contact the 

 scapula and coracoid. 



There are four ossified radials. The outermost is the shortest and the only member 

 of the series attached to the scapula. The other members of the radial series are 

 attached to the coracoid, the innermost being the longest. There are two post- 

 cleithra. The dorsal one is rounded and scale-like. Anteriorly this element bears 

 a small prominence which lies medial to the cleithrum. The ventral postcleithrum 

 is an elongated curved roof. The upper end is somewhat flattened and lies against 

 the medial edge of the dorsal postcleithrum. 



There are 14 pectoral fin-rays, the outermost unbranched. All rays are segmented. 

 At the base of the upper half of the first fin-ray there is a triangular splint bone. 



Vertebral column. There are approximately 54 vertebrae (range 53-57) of which 

 about 20 are caudal. All centra are amphicoelous and pierced by the notochord. 



Most of the centra are isodiametric but those anteriorly are deeper than long. 

 Each centrum is marked laterally by numerous grooves separated by fine ridges, 

 some of which anastomose. The neural arches are autogenous. Each centrum 

 bears pits dorsally for their reception. The neural arches associated with the first 

 29 centra are expanded distally. Neural spines borne by these arches are slender, 

 straight and remain separate from their fellows of the opposite side. The vertebral 

 centrum which is incorporated into the neurocranium bears a neural arch somewhat 

 broader than those immediately behind, but the neural spine is considerably shorter. 

 The neural spines of the posterior abdominal and caudal region are stout and fused 

 to their partners of the opposite side. The neural arches which support caudal 

 fin-rays are modified for this function and are not considered here (see Hollister 



1936). 



All of the caudal centra have stout haemal arches and spines. The posterior 

 haemal spines are modified in support of the caudal fin-rays. Autogenous 



