TJie Cretaceous Fauna of Pondoland. 296 



moderately convex, so that the height of the valve is rather greater 

 at or near the posterior end of the hinge-line than elsewhere. Valves 

 divided into two parts by a rounded ridge extending from the umbo 

 to the postero-ventral extremity. The ventral part is flattened or 

 slightly concave and slopes rapidly to the ventral margin. The 

 dorsal part is rathei; larger than the ventral .part ; it is convex and 

 slopes gradually to the postero-cjorsal margiji. Umbones obtuse, 

 incurved. Surface of valves smooth except for growth-lines. 



Length 25 mm. ; height 10 mm. 



Affinities. — This species does not seem to be closely related to any 

 known form. M. araucana (d'Orbigny),"'- from the Quiriquina Beds, 

 although similar in some respects is easily distinguished by the 

 curvature of the ventral margin. 



il/. Dieneri, Bohm,f is more curved, especially on the dorsal side, 

 and the anterior extremity is more rounded. 



Family PECTINID^. 



Genus PECTEN, Miiller. 

 Sub-genus CHLAMYS, Bolten. 

 Pecten (Chlamys) amapondensis, Griesbach. 

 Plate XXXV., figs. 7-9. 

 1871. Pecten amapondensis, Griesbach, Q.J.G.S., xxvii., p. 66, 

 pi. iii., fig. 7. 

 Description. — Shell small, ovate, pointed dorsally, slightly inequi- 

 lateral, a little higher than long, antero- and postero-dorsal margins 

 nearly straight, the remaining margin forming a regular curve. 

 Apical angle about 95°. Eight valve moderately convex with from 

 11 to 15 radial ribs. On the dorsal part of the valve these ribs are 

 strong and separated by deep furrows; ventrally they become 

 broader and less prominent, and are separated by shallow inter- 

 spaces. Towards the anterior and posterior margins also the ribs 

 are less distinct than on the middle of the valve. In the furrows on 

 the dorsal part of the valve fine, rather irregular, radial striae occur. 

 Numerous fairly regular concentric lamellae are present ; but appear 

 to be absent near the umbo, and are closer together on the ventral 

 than on the more dorsal parts of the valve. Anterior ear rather 



» Wilckens, Neues Jahrb. fur Min., &c., Beil. Band xviii. (1904), p. 227, 

 pi. xix., fig. 4. 



f Zeitschr. d- deutsch. geol. Gesellsch,, vol. Iii. (1900), p, 218, pi. vii., fig. 12. 



