276 



CRETACEOUS LAMELLIBRANCHIA. 



Nou 1905. Inoceramus Cripsi, T. Wcgner. Zeitschr. d. deutsch. geol. Gesellseh., 



vol. Ivii, p. 161. 



— 1906. — Crikpianus, /. rcthi]. Palaeontographica, vol. lii, p. 232. 



— 1908. — CKirsii, A. Slojnnojf. Ann. grol. miu. Russie, vol. x, p. 121. 



Descrijjtiov. — Shell tliiii, e(iuiv;ilvc, moderately inequilateral, convex between 

 the umbo and the vendnl margin; postero-dorsal part compressed and flattened; 

 antero-dorsal marginal part neai'ly perpendicular to the plane of the valves and 



Fig. a;!. 



■i 



Fig 34. 



Fiu.33.— Inofci-anufs Cnypsi. Mantell. The type, Britisli Museum (Nat. Hist.) No. 5893. Chalk Marl, 



Oftliam. Internal cast. Natural size. 

 Fig. 34.— Inoceramus Criprsl, Mantell. Chalk 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 ; jjosterior margin only slightly convex, 

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

 angle of about 140" Avith the antero-dorsal margin. Uml)ones iiiconsi)icnous, 

 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 irregular concentric ribs, 

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

 the ribs is unsymmetrical ; the anterior part curves rapidly, the postero-dorsal 

 })art is only slightly curved. 



Affinities.— A species from the Senonian was figured and described by Goldfuss 



