LEPIDOSTEOIDEI 



343 



of the jaw, the covering of the cheek vith small plates, the presence 



A. 



B 



FIG. 322. 



Lcpidostcus osseus, L. A, vertebra from in front ; 

 B, vertebral column of trunk, right-side view. (After 

 Balfour and Parker.) 1, convex anterior surface of 

 centrum ; 2, concave posterior surface of centrum ; 

 3, neural arch (basidorsal) ; 4, neural canal ; 5, inter- 

 dorsal cartilage ; 6, longitudinal ligament ; 7, neural 

 spine ; 8,transverse process of centrum (parapophysis). 



Fio. 323. 



Heart of Lepidosteus osseus, L. I, 

 ventral view. II, conus arteriosus 

 opened, a, atrium ; b, conus ; e, /, g, 

 transverse rows of valves in conus ; h, l~, 

 I, m, four afferent branchial vessels ; v, 

 ventricle. (From Giinther.) 



Fio. 3-24. 



Lepidostens oxsnm, L. 1, nostrils ; 2, pectoral, 3, pelvic, 4, anal, 5, caudal, 

 and 6, dorsal fin. 



of an interorbital septum and of paired fulcra, and the absence 

 of a median gular, Lepvlotus approaches the structure of this 



