FAUNA OF OKTHAULAX PUGNAX ZONE. 93 



Family CERITHIOPSIDAE. 



Genus CERITHIOPSIS Forbes and Hanley. 



Cerithiopsis Forbes and Hanley, Brit. Moll., vol. 3, p. 364, 1853. Type, 

 Murex tubercularis Montagu. 



CERITHIOPSIS SILICATA, new species. 



Plate 12, fig. 19. 



Shell small with an acute apex, later becoming subcylindrical ; 

 nucleus lost, the next 2 or 3 whorls with 2 elevated spiral threads 

 and no axial sculpture, followed by whorls with 3, gradually increas- 

 ing to four straplike spirals OA^er riding numerous axial stouter 

 rounded ribs with equal interspaces extending nearly from suture 

 to suture, and forming nearly square deep equal pits by their inter- 

 sections; suture close, but the elevated spirals on each side of it 

 give it a deeply channelled aspect; there are three spirals on the 

 rather convex base diminishing in size forward, but only incremental 

 axial sculpture; aperture defective, but without lirae; remaining 

 whorls in all, 10. Height, 6.5 ; maximum diameter, 2 mm. 



Tampa silex beds at Ballast Point, Tampa Bay, Florida; Dall. 

 U. S. Nat. Mus. No. 165.111. 



Family TRICHOTROPIDAE. 



Genus TRICHOTROPIS Broderip and So-werby. 



Trichotropis Broderip and Sowerbt, Zool, Journ., vol. 4, 1826, p. 373. 

 Type, Turbo hicarinatus Sowerby. 



Subgenus CEEITHIODERMA Conrad. 



Cerithioderma Conrad, Journ. Acad. Nat. Sci. Phlla., ser. 2, vol. 4, p. 295, 

 March, I860.— Dall, Trans. Wagner Inst., vol. 3, pt. 2, p. 293, 1892. 



TRICHOTROPIS (CERITHIODERMA) PRIMA Conrad. 



Cerithioderma prima Conrad, Journ. Acad. Nat. Sci. Phila., ser. 2. vol. 4, 

 p. 295, pi. 47. fig. 30, I860.— Dall, Trans. Wagner Inst., vol. 3, pt. 2, 

 p. 293, 1892. 



Mesostoma rtigosa Heilprin, Proc. Acad. Nat. Sci. Phila.. 1879, p. 215, 

 pi. 13. fig. 13.— Meyer, Ber. Senckenb. Ges., 1887, p. 18. 



Middle and upper Eocene of Claiborne, Mississippi, and Lisbon, 

 Alabama. Oligocene of the Tampa silex beds? U. S. Nat. Mus. 

 No. 113394. 



The specimen from Ballast Point is in such poor condition that 

 the identification of the species is doubtful. 



