The Cretaceous Fauna of Pondolancl. 303 



Family CEASSATELLITID^. 



Genus Crassatellites, Kriiger. 



Crassatellites africanus, sp. nov. 



Plate XXXV., fig. 21. Plate XXXVL, figs. 1-3. 



Description. — Shell triangular, high, regularly convex, but with 

 a narrow, flattened area extending from the umbo to the posterior 

 margin ; height sometimes only a little less than the length. Antero- 

 dorsal margin slightly convex. Anterior margin well rounded and 

 passing into the curved ventral margin. Postero-dorsal margin 

 very long, with a steep ventral slope, slightly curving or sinuous. 

 Posterior margin very short, obhque. Posterior angle rounded. 

 Umbones pointed, only slightly curved. Lunule large, with a sharp 

 edge. Escutcheon large, with its edge sharply defined dorsally, but 

 becoming indistinct ventrally. 



Ornamentation consists of strong concentric ribs separated by 

 broad furrows. Smaller ribs occur between the stronger ribs. The 

 latter become less distinct towards the ventral margin of the valve, 

 and usually die out at or near the margin of the small posterior area, 

 but on the dorsal part of the valve they are sometimes continued to 

 the margin of the escutcheon, bending at an angle in passing on 

 to the posterior area. Margin of valves crenulate. 



Length 34 . 33 . 33 . 31 . 29 . 28 mm. 

 Height 31 . 29-5 . 27-5 . 29 . 25 . 25-5. „ 



Affinities. — This species is distinguished by the very small posterior 

 area, and the very short posterior margin which gives a triangular 

 outline to the valve. It is somewhat similar to G. compactns, Gabb,"'' 

 but is relatively higher, and is clearly distinguished by the strong 

 concentric ribs. Two species of Crassatellites occur in the Ariyalar 

 Group, f but they are quite distinct from C. africanus. 



* Geol. Surv. Califorma, Palajont. ii. (1869), p. 190, pi. xxx., fig. 85. 



t Stoliczka, Cret. Fauna S. India (1871), pp. 29.5, 296, pi. v., figs. 12-19. 



