292 [Oct. 1847. 



3, Cardium diver mm. 



Trigonal, ventricose, subequilateral, thiii, with concentric lines and more 

 approximate, fine, but obtuse radiating lines ; umbonial slope rounded, and the 

 posterior space from the umbonial slope with profound radiating striae ; posterior 

 side slightly waved or contracted; summits very prominent; basal margin 

 rounded in the middle, contracted posteriorly: posterior extremity subtrunca- 

 ted ; inner margin densely crenate. Height 12-10. Length 13-10. Abundant. 



Allied to C. Nicolleti, nob. When viewed through a magnifier, the inter- 

 stices of the concentric lines have a singular imbricated appearance. 



4. Cardium Vicksburgense. 

 Cordate, ventricose, with about twenty-four ribs; angular and profound; 

 towards the anterior margin obsolete ; summit prominent ; nearest the anterior 

 end; anterior margin nearly straight and direct; posterior end subtruncated. 

 Height 3-10. Length 4-10 nearly. Rare. 



1. Tellina pectorosa. 

 Subtriangular, elevated, smooth and polished ; ventricose ; beaks medial ; an- 

 terior end obtuse, rounded ; posterior side somewhat cuneiform, with a slight 

 wave or fold; basal margin profoundly rounded. Length 6-10. Height 

 5-10. 



2. Tellina serica. 



Elliptical, inequivalved ; beaks nearest the posterior end ; concentric lines 

 very minute anl closely arranged; anterior side slightly bent or reflected. 

 Length 7-10. 



3. Tellina Vicksburgensis. 



Triangular, small, with regular minute concentric lines ; anterior end rounded; 

 posterior submargin angular or obscurely carinated, the end obliquely trunca- 

 ted ; posterior side shortest, and slightly bent or waved; lateral teeth in the 

 right valve only. Length 3-10. Height \. 



Donax funerata. 



Triangular, small, convex, with obsolete radiating lines ; anterior side short, 

 end truncated, direct; margin within finely crenulated ; lateral teeth none. 

 Length 3-10. 



Very rare. I found it about 8 miles N. E. of Vicksburg. 



1. Cytherea Astartiformis. 



Trigonal, elevated, ventricose, subequilateral, with numerous regular concen- 

 tric grooves and obtuse ridges ; lunule not defined ; summits prominent ; umbo 

 flattened. Length 6-10. Height . 



This shell has a remarkable resemblance on the exterior to some species of 

 Aslarle. Rare. 



2. Cytherea imitabilis. 



Cordate, inequilateral, plano-convex, with numerous concentric prominent 

 acute ribs; extremities rounded ; basal margin regularly curved ; lunule ovate, 

 defined by an impressed line. Length 1 7-10. Height 1 3-10. Common. 



