231 St. Maurice and Claiborne Pelecypoda 231 



PLATE 30 

 Figure Page 



1-5. Venericardia alticostata Conrad 82 



Fig. I, 34 mm., form of siUimaniii Lea. Claiborne. 



2, 19 " a still shorter form, but showing pro- 

 nounced sub-ligamental costation exteriorly. Clai- 

 borne. 



3, 41 mm., practically the form described as transversa 

 by Lea. 



4, 48 mm., large transverse form, showing the fourth 

 rib below the ligamental margin to be the largest of 

 all on the post-umbonal slope. Claiborne. 



5, 45 mm. , interior of a large transverse typical Clai- 

 borne form. 



6-9. Venericardia trapaquara Harris .-.Si 



Fig. 6, 14 mm., approaching carsonensis. Wautubbee. 



7, 13 " Clear Lake, La. 



8, II *' type specimen. Tex. Museum. 



9, X 2.5, showing crenulae well preserved. Wautubbee. 



10, 13-16. l^enericardianatchitoches, n. sp 82 



Fig. 10, 16 mm.. Natchitoches, La. 



13-16, X 1.5 ., fragments showing surface and 

 hinge characters. Natchitoches, La. 



11. VeneHcardia wilcoxensis Dall 85 



Showing the U-shaped inter-costal spaces with well-devel- 

 oped microscopic granules. From the Midway Eocene at 

 Matthew's Landing, Ala. 



12. Venericardia alticostata Conrad. Showing the narrow, al- 



most V-shaped intercostal spaces with microscopic gran- 

 ules. 'Claiborne. 



