276 



CliETACEOUS LAMELLIBKANCHIA. 



Noil 11105. Inockramus Cripsi, T. Weyuer. Zoiisclir. J. Joutscli. geul. Gesellscli., 



vol. Ivii, p. 161. 



— 1906. — Crispianus, /. PelhiJ. Palseontograpliicii, vol. lii, j). l'32. 



— 1908. — Cripsii, a. StojaiKiff. Ann. gi'ol. min. Russie, vol. x, p. 121. 



Descr'ipiio)!. — Shell thin, (Miuivalve, inodenitely inequilateral, convex between 

 the umbo and the vential margin ; postcro-dorsal part compressed and flattened ; 

 antcro-dorsal marginal part ncaih' jieijicndicular to the plane of the valves and 



Fig. 33. 



Fio .34. 



Fia.33.— J«oferami(s Cripyii^i. Maiitfll. Tlic tyiu^, Biitisl. Mu.seum (Nat. Hist.) No. o8y3. Chalk Marl, 

 Oft'hnin. IntiTiinl cast. Natural size. .... 



Fio. -i-l.—Inocerarnvs Crippsi, Mantoll. Clialk Marl. Internal cast of a left valve similar to the type. 

 British Museum (Nat. Hist.) No. 589.5. Natural size. 



nearly straight. Ventral margin convex ; posterior margin only slightly convex, 

 aiul forming more than a right angle with the hinge-line. Hinge-line forms an 

 angle of about 1 10" with the antero-dorsal margin. Umboncs inconspicuous, 

 pointed, not curved, at about a third of the length of the hinge from the anterior 

 end ; in front of the umbones is a small, obtusely triangular ear. 



Ornamentation consists of broad, rounded, rather iiii'gnlar concentric ribs, 

 which are strong anteriorly, and liecoine weaker posteriorly. The curvature of 

 the ribs is unsymmetrical ; the anterior part curves raiiidly, the po.stero-dorsal 

 part is only slightly curved. 



Ajfiidtiea. — A species from (lie .i-'enonian was figured and described by Goldfuss 



