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1365 



TERTIARY FAUNA OF FLORIDA 



terminates distally in an indentation of the margin which, as it were, loops up 

 the line of the profile ; surface sculptured with incremental lines and regularly 

 spaced, rather distant, slightly elevated and recurved concentric lamellae ; lunule 

 small, cordate, deep, overshadowed by the gyrate umbones ; escutcheon none ; 

 anterior end of the valve below the anterior dorsal area projecting, subangular ; 

 hinge and adductor scars normal. Height 13.5, length 14.0, diam. lo.o mm. 



This shell is near P. cariniferus Conrad, but is less solid, less inflated, with 

 the concentric sculpture more distinct and distant, the dorsal areas larger and 

 more emphatically impressed, and the margin of the valves smooth, not crenu- 

 late. 



Phacoides (Here) -wacissanus n. sp. 

 Plate 50, Figure 15. 



Oligocene of the silex beds at Ballast Point, Tampa Bay, and Wacissa, 

 Jefferson County, Florida; Crosby, Burns, Shepard, Dall, and Eldridge. 



Shell much resembling in general appearance and solidity P. cariniferus, 

 but having the beaks lower, the posterior dorsal area larger but not so deeply 

 impressed, the anterior dorsal area less impressed, larger, and without the 

 carina and marginal projection below it which occurs in that species ; the shell 

 is also rather longer and less high, and the hinge-teeth are longer and heavier 

 than in P. cariniferus. The margins are finely crenulate, and well-grown speci- 

 mens often exhibit resting stages near the base, indicated by sulci. Alt. 15, 

 Ion. 16, diam. 12 mm. Large specimens attain a length of 20 mm. 



Rather common in the silex beds at Ballast Point. 



Phacoides (Here) podagrinus n. sp. 

 Plate 50, Figures 12, 13. 



Oligocene of the Bowden, Jamaica, marl, and of beds of similar age at 

 Curaqao. 



Shell when young moderately convex, when senile having an exaggerated 

 thickness and almost spherical convexity. It belongs to the group of P. pensyl- 

 vanicus L., of which species it is doubtless a precursor, and the mention of that 

 species by Gahb and Guppy in the " Miocene" (=: Oligocene) of St. Domingo 

 and Jamaica doubtless refers to the present fossil. For this reason it is best 

 described by comparison with P. pensylvanicus, from which it differs by its 

 smaller size and greater inflation at maturity, its finer and closer concentric 

 sculpture, its shorter and broader posterior dorsal area, its less elevated beaks, 

 its slightly smaller and more distinctly limited anterior dorsal area, and its more 



