Bulletin 24 , 58 



finer incremental lines occur, and fine, radial, vermicular striae 

 interior of shell roughened, and with a long, lucinoid anterior, 

 muscle scar. 



Height 2j , ividth 32, thickness 7 mm. 

 This species resembles P.foremani Con. of the Calvert form- 

 ation of Maryland. The shell differs in being less rotund, more 

 inflated, thinner and with the posterior dorsal slope much less im- 

 pressed. The anterior extremity is likewise much more wing- 

 like, with the lunuledeep but short, which, in P. foremaniis typ- 

 ically more elongated. Young shells of both P. foremani and 

 P. anodonta with rather thin shells usually show a strong develop- 

 ment of radial lines or rays in the interior ; and the umbonal cav- 

 ity is generally filled with a deposit of prismatic shell substance. 

 The interior of the shell shows no development of these rays, 



Florida ; Miocene, Upper bed at Alum bluff 



Venericardia (Pleuromeris) scituloides, n. sp., Pate 1, Fig's 1-3 



Shell small, solid ; equilateral, convex triangular in shape ; 

 sculpture of 7-9 flat, broad ribs separated hy narrow interspaces ; 

 umbones with the ribs coarsely or evenly granulated or sometimes 

 smooth ; on the basal portion, the ribs are crossed by coarse con- 

 centric lines ; lunule smooth, very deep, elongated and of a length 

 roughly one-half the height of the shell ; escutcheon smooth, lan- 

 ceolate ; hinge rather high and heavy ; internal margin fluted by 

 the exterior ribs. 



Height 5.50, width 4.75, thickness 5.50 mm. 



This species bears much resemblance to V. scitula Dall of the 

 Oligocene of the Oak Grove sands Florida. The most marked dif- 

 ferences are the fewer ribs, those of V. scitula ranging from 12 to 

 14 in number and in having these ribs separated by narrower in- 

 spaces. From V. tridentata Conrad, the species is distinguished 

 by its fewer ribs and by its shape. 



Florida ; Miocene of the upper bed at Alum Bluff. 



