546 



TELEOSTEI 



Fam. 4. Leptolepididae. Praemaxillaries very small ; maxil- 

 laries large, loosely attached ; teeth small and conical. Parietal 

 bones separating the supraoccipital from the frontals ; opercular 

 bones well developed. Vertebral centra well ossified, but always 

 pierced by the notochord ; ribs delicate ; epipleurals present ; no 

 fused or expanded haemal arches at the base of the caudal 

 fin. Dorsal and anal fins small, the former above or behind the 

 ventrals. Ventrals with 5 to 10 rays. Scales thin, cycloid and 

 deeply imbricate, usually coated with ganoin in their exposed 

 portion. 



FIG. 325. Leptolepis dubius. (Restoration of skeleton by A. S. Woodward.) 



Leptolepis, with numerous species, from the Jurassic and Cre- 

 taceous of Europe and New South Wales ; Vidalia, Jurassic of 

 France ; Aethalion, Jurassic of Bavaria ; Thrissops, Jurassic and 

 Cretaceous of Europe ; and Lycoptera, Jurassic of Asia. 



Fam. 5. Elopidae. Margin of the upper jaw formed by the 

 praemaxillaries and the maxillaries, the latter the more developed, 

 and movably articulated above the former to the ethmoid. 

 Parietal bones in contact behind the frontals: opercular bones 

 well developed. Basis cranii double. A bony intergular or 

 subliugual plate. Jaws, palatines, pterygoids, vomer, para- 

 sphenoid, glossohyal, and pharyngeals toothed. Eibs mostly 

 sessile, inserted very low down, behind parapophyses ; epineurals 

 similar to the ribs, but directed upwards. Pectorals low down, 

 folding like the ventrals. Post -temporal forked, the upper 

 branch attached to the epiotic, the lower to the opisthotic ; 

 post-clavicle small ; scapular foramen in the scapula ; pterygials 

 well developed, three in contact with coracoid. Ventrals with 

 10 to 16 rays. Branch iostegal rays very numerous (over 20). 

 Air-bladder large. 



