SUB-CLASS I 



SELACHII 



33 



denticles, and the pulp cavity completely filled with vasodentine. Vertebral centra 

 with eight bifurcating plates tvhich radiate outwards. UiDper Jurassic to Eecent. 



Orthacodus, Sm. Woodw. (Sphenodus, Ag., non Gray, nee Lund), (Fig. 63). 

 Teeth very slender and erect, compressed, without lateral 

 denticles ; the root broad and depressed, simple. 0. longidens, 

 Ag. sp. (Fig. 63), and other species are Upper Jurassic. 

 Apparently also a Lower Cretaceous genus. 



Scapanorhynchus, Sm. Woodw. [lihinognathus, Davis non 

 Fairmaire ; 1 Mitsukurina, Jordan). Body slender, snout 

 much elongated. Second dorsal fin small, opposed to a 



much extended anal fin ; caudal 

 fin much elongated, inferiorly 

 notched near the extremit3^ Teeth 

 as in Odontaspis. Complete 

 skeletons of S. lewisi, Davis sp., 

 and S. elongatns, Sm. Woodw., from the Upper Cre- 

 taceous of Sahel Alma, Mount Lebanon. Detached 

 teeth (»S'. rhaphiodon, Ag. sp.) in Upper Cretaceous 

 of Europe, probably also in North America, India, 

 and New Zealand. Apparently living in the deep 

 sea off" Japan (Mitsukurina owstoni, Jordan). 



Odontaspis, Ag. (Triglochis, M. and H. ; Otodus, 

 Ag. in part.), (Fig. 64). Snout not much elongated. 

 Second dorsal fin and the anal of equal size, scarcely 

 smaller than the first dorsal. Side of tail without 

 keel. Teeth with a slender principal cusp, with 

 sharp lateral edges, flattened outer face, and convex inner face, also one or 

 two pairs of small lateral denticles ; root large and bifurcated. Upper 



Fig. 63. 



OrtJtaoodus longidens, 

 Ag. sp. White .Jura y ; 

 Bollert, AViirtemberg. 



Odontaspis cuspidata, Ag. sp. 

 Oligocene ; Weinlieini, near Alzey. 



Vertebra of Lamna, in front (A) and side view (jS), and in vertical median section (C). Nat. size. 

 A, B, From Oligocene of Flonheim. C, From London Clay, Slieppey. 



Cretaceous, Tertiaiy and Eecent. 0. bronni, Ag. U. Cretaceous, Maastricht 

 and Ciply. 0. elegans, Ag. sp., and 0. cuspidata, Ag. sp. (Fig. 64), from 

 Lower Tertiaries. 



Otodus, Ag. (Figs. 65-67). Very robust teeth with stout lateral denticles, 



VOL. II D 



