80 Geological Survey of Alabama. 



on the ventral part, however, about half of them vanish rather suddenly 

 posteriorly, and the rest of them increase in size, so that the posterior part 

 is covered by fewer but larger ribs. Many of the specimens have one or 

 two indistinct radiating furrows on the anterior part. In some, the con- 

 centric ribs become erased like on the anterior part (see loc. eft). 



LEDA TRIANGULATA, n. sp. PL 3, fig. 14. 



Triangular ; ventral margin rounded ; near equilateral ; ventricose ; 

 hinge-plate long and broad ; surface nearly smooth, with indistinct con- 

 centric lines ; margin entire. 



Locality. Red Bluff, Miss. 



I found only the figured specimen. 



LIMOPSIS RADIATUS, Meyer. PL 3, figs. 17, 17a. Am. Jour. ScL, 

 XXIX., 1885, p. 459. 



Rounded, quadrangular; solid; hinge teeth, diminishing in size near 

 the pit ; surface covered by alternating radiating ribs, crossed by equal 

 closely set, elevated concentric lines ; the points of crossing are thick- 

 ened by nodules ; margin crenulate within. 



Locality. Jackson, Miss. Common. 



The similarity of this species with Lytnopsis obliquus, Lea, sp., is 

 pointed out in the above cited place. 



ASTARTE PROTRACTA, 11. Sp. PL 3, figS. 18, 18a. 



Elongated, subquadrangular ; umbonial part strongly flattened ; adduc- 

 tors prominent ; surface covered with distant concentric ribs, becoming 

 obsolete on the umbonial part ; margin entire. 



Locality. Enterprise, Miss. 



The single specimen was collected by me in the stratum, in Enterprise, 

 mentioned Am. Jour. Sci., XXX., 1885, p. 70, as upper bed. 



ASTARTE TRIANGULATA, n. sp. PL 3, figs. 21, 2 la. 



Trigonal, solid ; pedal scar of anterior adductor distinct ; lunule long 

 and flat ; surface closely covered with concentric ribs ; margin crenulate. 

 Locality. Red Bluff, Miss. Common. 



The concentric ribs vary in size, in different ^.HM-imrns, and in some 



