264 PROCEEDINGS OF THE ACADEMY OF [Feb., 



from the latter in the form of the anterostral sinus, which is 

 longer and more transverse in outline, in the form of the lunule, 

 which is larger and very much more elongate, and in the cardinal 

 tooth of the right valve, which is here scarcely at all oblique, 

 being almost perpendicular to the hinge line. In both species the 

 laterals are moderately developed and the ventral edges smooth 

 internally without trace of crenulation. Length of a moderately 

 large specimen 7 mm., height 6.2 mm. The anterior and posterior 

 sides are almost equally and very broadly rounded. This species 

 is very shghtly more inflated than vicksburgensis. There is a variety 

 which is very abundant in the Jacksonian of Moody's Branch. 



In the Conrad collection the only species of Lucina that I could dis- 

 cover is the largest form occurring at Vicksburg — moderately convex, 

 very thin in substance, with feeble hinge and nearly smooth surface. 

 The label attached states that this is Lucina perlevis. This is, however, 

 the species which w^as subsequently described under the name missis- 

 sippiensis. There is some confusion here. 



Venericardia vicksburgensis n. sp. 



The larger Venericardia of the Vicksburg differs specifically from 

 the one occurring so abundantly in the Jackson — named diversidentata 

 by Meyer — and also rotunda of the Claiborne, in having very much 

 fewer radiating ribs, these being only 19-20 in number. It is found 

 only in the lower hmestone, and attained a length of 22 mm. or more. 

 It occurs also at Red Bluff. 



Cardita aldrichi n. sp. 



Lower limestone at Vicksburg occurring in considerable abundance. 

 It is only moderately convex, inequilateral, with about 15 broad, feebly 

 convex, approximate radiating ribs. The longerribs, behind the middle, 

 are more notably wide and separated throughout their length by 

 scarcely half of their own width. The anterior lateral hinge tooth is 

 distinct. The length of a specimen rather more than half grown is 5.5 

 mm., the height 4.5 mm. 



Area invidiosa n. sp. 



From the Red Bluff formation of Mississippi I have before me speci- 

 mens of a small Area, probably allied somewhat to the Claibornian rliom- 

 hoidella of Lea. It is subrhomboidal, very inequilateral, moderately 

 inflated, broadly rounded ventrally, the anterior and posterior sides 

 oblique, the former rounded, the latter longer and nearly straight. 

 The beaks are rather broad, moderately elevated above the hinge-line, 

 bisected by a feeble depression which becomes obsolete ventrally. 



