UPPER, OR FLINTY CHALK. 241 



Tab. xxix. fig. 6, the tongue detached from a large specimen. 



Tab. xxxiv. fig. 7, a vertical section of the head, the tongue remaining 

 in situ. 



Locality. Lower ohalk, near Lewes. 



118. The lower jaw; vertebra, &c. of an unknown fish? Tab. xlii. 



The fossils delineated in this plate were imbedded in the same block 

 of chalk, and most probably belonged to the same individual. They con- 

 sist of part of the lower jaw, several tusks or defences, a vertebra, and a 

 cylindrical bone. 



The jaw, fig. 1, of which the right side only remains, is attached to 

 the chalk, by its inner surface, the exterior being exposed. It is 5-5 

 inches long ; 1 -2 inch wide ; and 0*5 inch thick in front : it contains twelve 

 smooth pointed teeth. These are sHghtly convex, very brittle, and 

 possess a glossy surface. 



The three anterior ones are gently curved ; their fangs are hollow, 

 and placed in sockets that extend almost to the base of the jaw. The 

 nine posterior teeth are of a lanceolate form, and probably destitute 

 of fangs, appearing as if attached to the jaw by anchylosis. The two 

 anterior and posterior teeth of this set, are placed close to each other ; 

 one of them is very small and dehcate. A fragment of bone is imbedded 

 immediately above the posterior part of the jaw ; and although it is too 

 imperfect to admit of any satisfactory conjecture of its nature, yet there 

 seems reason to suppose, that it may be the remains of a palate bone. 



The specimens figs. 3, and 4, are corresponding portions, and were by 

 accident broken from the front of the jaw ; but the edges of the respective 

 pieces were so much mutilated, that I have been unable to ascertain the 

 precise situation they originally occupied. They consist of a portion of 

 the jaw, with the remains of five tusks or defences, only one of which is 

 entire ; these resemble the teeth in the fossil figured by Faujas St. Fond, 

 Hist. Nat. de la Montagne de St. Pierre, Tab. xix. fig. 10 ; which that 

 distinguished naturalist describes as "Portion de machoire d'lm poisson 

 inconnu.'" 



The vertebra (fig. 2.) is deeply concave on both sides, and the inner 



II 



