802 CRETACEOUS LAMELLIBRANCHIA. 



tuberculatc cliaracter to the larger concentric ril)?. On the posterior part of the 

 shell the concentric ribs bend sharply npwards. 



Bcmarls. — Only two imperfect specimens of this species have been seen ; it is 

 closely allied to I. Inhalnx (p. 29G), but differs in the presence of radial ribs, the 

 greater development of the larger concentric ril)s, and in the greater convexity of 

 the valves. 



Tiiiv'. — From the Senonian of Quedlinlnirg. 



Distribution. — Upper Chalk ([)robably zone of ^Irtinoi-intia.v ijinatrafus) near 

 Speeton, and the sonth of England (probably Kent). 



Inoceuamts Tur.EKcur.ATi's, sp. nov. Plato lAY, fig. 8. Text-fig. -59. 



1882. Inoceramus c.\rdissoides, II. Srlii-i'uh'r. Zc-itxlir. d. deulscli. geol. 



Gesellsch., vol. xxxiv, p. 271, 

 pi. xvi, fig. 1 (Non Goldfuss). 



Besi-rijifidii. — Shell very inequilateral, ol)li(|ue, niucli higliei- than long; dorsal 

 part moderately convex, ventral part only slightly convex. Umbones relatively 

 small, nearly terminal. Antero-doi'sal ai-ea flattened, nearly smooth. A rounded 

 depression, separated from the posterior Aving-like part, passes from the umbo to 

 the postero-ventral extremity. Hinge-line forms less than a right angle with the 

 anterior margin. 



Ornamentation consists of numci'ous concentric ribs which, at a short distance 

 from the umbo, are crossed by radial furrows, so that the ribs appear then 

 to consist of rows of tubercles ; on the sides of the shell the radial furrows, 

 and conserpiently also the tubercles, are less distinct than on the middle of 

 the shell. 



AJfiiiities. — This species is allied to /. Inhntiis and /. cardissoides, but differs in 

 the greater development of the radial ribs, which give rise to a tuberculate type 

 of ornamentation ; also the stronger concentric ribs which occur in I. ca)xlissoides 

 are small or altogether wanting. The English specimens agree fairly closely with 

 the example figured by Schroder as 7. cdrdissoidi's. 



Tijpc — In Dr. Rowe's Collection. 



Distrilmtioii. — Upper Chalk (zone of Actiiwcamax (jiiadratns) of Brighton, and 

 Sewerby (Yorkshire). 



