294 



CRETACEOUS LAMELLIBRANCHIA. 



Description. — Shell equivalve, very inequilateral, slightly or moderately convex, 

 becoming very convex in old specimens, in which the later part of the shell grows 

 either perpendicularly to or at an obtuse angle with the earlier part ; posterior 



Fig. 51. — Inoceramus baltirus, Bolim. Senonian, Worbarrow Bay, Dorset. British Museum, No. L22177. 

 Flint cast. Eitflit valve and anterior view. Natural size. 



Fig. 52. — Inoceramus balticus, Bohm. Anterior view of specimen shown in Fig. 53. x %. 



and postero-dorsal parts compressed ; length greater than height, the difference 

 increasing with age. Anterior and ventral margins rounded ; posterior margin 

 forming 1 an obtuse angle with the hinge. Hinge-line long. Umbones rather 

 small, nearly terminal. 



