FAUNA OP ORTHAULAX PUGNAX ZONE, 117 



LEDA FLEXUOSA Heilprin. 



Plate 23, figs. 8, 10. 



Leda flexuosa Heilprin, Trans. Wagner Inst., vol. 1, p. 119, pi. 16, fig. 66 

 (two views) 1887. — Dall, Trans. Wagner Inst, vol. 3, pt. 4, p. 589, pi. 

 38, figs. 5, 5a, 1898. 



Tampa silex beds at Ballast Point, Tampa Bay, Florida ; Heilprin' 

 and Dall. IT. S. Nat. Miis. No. 16.5170. 



Since the original figures were very obscure, better ones are now 

 provided. 



LEDA POSTI, new species. 



Plate 21, figs. 6, 9. 



Shell small, thin, equivalve, inequilateral, slender, rounded in 

 front, attenuated and bluntly pointed behind; basal profile gently 

 arcuate, anterior dorsal slope slightly convex, posterior slope nearly 

 direct ; beaks low, much incurved, opisthocoelous ; no distinct lunule, 

 but a narrow impressed space in front ; behind the beaks a long nar- 

 row escutcheon extending to the end of the valve with the cardinal 

 margins pouting; sculpture of incremental lines more prominent 

 near the beaks and base, nearly obsolete on the middle of the valve; 

 near the base these become sparse and sublamellose in the type- 

 specimen; interior smooth; the muscular scars small, not thickened; 

 hinge with about 20 anterior and 19 posterior V-shaped small teeth 

 separated by a well-marked subtriangular resiliifer, wholly internal 

 and just below the beaks. Length of valve 14 mm., of posterior end 

 8 mm., height 6.7 mm., maximum diameter 5 mm. 



Tampa silex beds Ballast Point, Tampa Bay, Florida. Type- 

 specimen from the Post collection. U. S. Nat. Mus. No. 165171. 



Genus YOLDIA Moller. 



Yoldia Moller, Index Moll. Groenl., 1842, p. 18. First species, TolMa 



arctica Gray, as Nuciila. 

 Yoldia Dall, Trans. Wagner Inst., vol. 3, pt. 4, pp. 593-4, 1898. Type, Y. 



glacialis Wood. 



YOLDIA FRATER Dall. 

 Plate 4, fig. 5. 



Yoldia frater Dall, Trans. Wagner Inst., vol. 3, pt. 4. p. 590, pi. 32. fig. 1, 

 1898. 

 Oligocene of the Chipola marls in Calhoun and Walton Counties, 

 Florida; and of the Oak Grove sands at Oak Grove, Santa Rosa 

 County, northwest Florida ; Dall. U. S. Nat. Mus. No. 165172. 



A small Yoldia obtained at Ballast Point from the Tampa silex 

 beds appears to be the young of this species. 



