TRANSACTIONS OF WAGNER 

 1270 



TERTIARY FAUNA OF FLORIDA 



This is a well-characterized and interesting species. The lunule is defined 

 only by a feebly incised line which is often indistinguishable in partly worn 

 specimens. The hinge is massive for the size of the shell, the pallial sinus 

 angular and nearly horizontal, and the basal margins entire. The concentric 

 sculpture is low and rounded over the greater part of the disk, becoming 

 higher and sharper near the posterior end of the shell. The specimens I have 

 seen from Vicksburg are from the clay bed and not the marl, and I do not know 

 whether they also occur in the marl or not. 



Pitaria ( Lamelliconcha ) calcanea n. sp. 

 Plate 55, Figure 19. 



Oligocene of Vicksburg, Mississippi ; Johnson and Crutcher. 



Shell small, solid, subtrigonal, elevated, with prominent anteriorly twisted 

 beaks ; lunule impressed, obscurely limited by an impressed line, rather large, 

 cordate ; an obscure ridge extends from the beaks backward and downward 

 to the lower posterior end of the shell ; anterior end attenuated, rounded ; 

 posterior end broader and more bluntly rounded ; base arcuate ; sculpture of 

 thick, adjacent, low, rounded concentric ribs, smooth except for the ribbing ; 

 when partly eroded showing fine, thread-like, concentric structure; nymphs 

 short; hinge solid, concentrated, the teeth entire, the posterior left cardinal 

 slender, the anterior lateral stout and prominent ; internal margins entire ; 

 pallial sinus linguiform, slightly ascending, not reaching the middle of the 

 shell. Length 17, height 15, diameter 10 mm. 



This shell is somewhat rude and individuals differ somewhat in form, but 

 all show the elevated and twisted beaks and the broad, low, thick ribs, differ- 

 ing from P. astartiformis, which has narrow ribs terminally acute, separated 

 by deep channels. 



Pitaria (Lamelliconcha) fllosina n. sp. 

 Plate 57, Figure i. 



Upper Miocene of North Carolina at the Natural Well in Duplin County; 

 Burns. 



Shell small, subcompressed, ovate-trigonal, with low, small, pointed beaks ; 

 lunule large, lanceolate, hardly differentiated from the rest of the surface by an 

 obscure impressed line, the surface of the lunule sculptured like the rest of the 

 shell and not impressed; surface with very fine, close, thread-like concentric 

 ribs but no radial sculpture ; hinge well developed but delicate ; the anterior 

 right, the posterior and anterior left cardinals entire, the others grooved or 



