St. Maurice and CIvAiborne Pelecypoda 131 



a vertical at their ventral edges, each leaf covered with radial raised lines 

 running in couples. Upper valve slightly convex, lower valve convex and 

 inequilateral. 



Resembles somewhat C. corticosa Con. , but is smaller and more pro- 

 fusely ornamented. One lower valve has twelve leaves or corrugations. 



Locality.— Th.& Ostrea sellcsformis bed, at White's Marl bed, Monroe 

 Co., Alabama. 



In our collection from Wautubbee, Hickorj^, and 8 miles W. 

 of Enterprise, Miss., and Orangeburg, S. C, made in 1898 there 

 are several valves of a Chama belonging presumably to Aldrich's 

 species though what he calls the upper valve seems to us to be 

 the attached valve. He does not figure the "lower valve". We 

 simply know that it is convex and one valve ' 'has 1 2 leaves or 

 corrugations' ' . In ours the upper valve is intensely foliate as 

 shown in the figure (fig. 3). 



A specimen of a lesser valve of a species with beaks gyrating 

 in the opposite direction from the above is shown as fig. 4, from 

 between Orrell's Crossing and Evergreen Crossing of Elm Creek, 

 lyce Co., Tex. 



Cardium harrisi Vaughan, PI. 41. Figs. 5-7. 



C. harrisi Vaughan, Bull. U. S. G. S., 142, 1896, p. 37, pi. 4, figs, i, 2. 

 C. {Tropidocardium) harrisi Dall, Trans. Wag., Ill, 1900, p. 1092. 



Vaughan' s original description. — Shell large, ventricose umbones 

 very prominent, incurved, situated about half-way between the anterior and 

 posterior terminations of the shell. Anterior portion somewhat rostrate ; 

 anterior margin gradually rounded. Base gently curved. The posterior 

 almost straight, rounding to meet the basal margin. Nineteen broad ribs 

 anterior to the umbonal slope.* Posterior to the umbonal slope the ribs do 

 not show on the cast. Length 74 mm. ; height (from basal margin to the 

 highest point of umbonal prominence), 70 mm., diameter, 56 mm. 



The figure and description are made from an excellent internal 

 cast. 



Specimens from Winn Parish show clearly that some of the ribs 

 on the post-umbonal slope are provided with huge saw-tooth-like 

 flat spines. Excellent material from the base of Claiborne bluff 



*The large variety of this species which may be call ed gainesense has 

 33-36 ribs "anterior to the umbonal slope." 



