TRANSACTIONS OF WAGNER 

 576 



TERTIARY FAUNA OF FLORIDA 



over most of the valve, but tending to be stronger near the anterior and 

 posterior slopes ; here and there one crosses the whole shell like the indication 

 of a resting stage ; dorsal slopes nearly straight, base arcuate, ends rounded ; 

 lunule absent, escutcheon impressed; striated, the margins not pouting in the 

 middle ; beaks prominent, obtuse ; interior brilliantly pearly, muscular im- 

 pressions deep; the basal margin finely crenulate; hinge strong, wide; the 

 chondrophore oblique, heavy ; anterior teeth wide, strong, about seventeen, 

 posterior about seven. Lon. of shell 4.75, alt. 4, diam. 2.5 mm. 



This species differs from the preceding by its more trigonal, heavy, and 

 pearly shell, its wider and proportionately heavier hinge, and its impressed 

 instead of merely flattened escutcheon. The Maryland specimens are usually 

 larger and more worn than the types from West Florida; both retain a purplish 

 tint in their nacre. 



Nucula taphria n. s. 

 PLATE 32, FIGURE 14. 



Miocene of Magnolia and the Natural Well, Duplin County, North Caro- 

 lina ; Burns. 



Shell small, very solid, rounded cuneiform, with few strong, distant con- 

 centric grooves, like marks of resting stages, which extend clear over the 

 shell, otherwise smooth ; beaks prominent, turgid ; lunule absent ; escutcheon 

 faintly indicated ; posterior end subtruncate, anterior produced and rounded, 

 base moderately arcuate ; interior hardly nacreous, muscular impressions 

 large and distinct ; basal margins entire ; hinge strong and heavy ; chondro- 

 phore wide, distinct, a little oblique ; anterior teeth thirteen, posterior six or 

 seven. Lon. of shell 2.9, alt. 2.25, diam. 1.5 mm. 



This interesting species is related to the recent N. delphinodonta Mighels, 

 which is a more rounded and less oblique shell, without the strong concentric 

 grooves of N. taphria. 



Nucula prunicola n. s. 



PLATE 32, FIGURE 9. 



Miocene of Plum Point, Maryland, Burns; and one mile south of Plum 

 Point, Harris. 



Shell small, inflated, polished, very inequilateral ; surface with obsolete, 

 obscure radial striae, stronger where they cross between the concentric ridges 

 and near the ventral margin ; beaks, dorsal slopes, escutcheon, and the poste- 

 rior two-thirds of the sides of the shell smooth or nearlv so; on the anterior 



