FAUNA OF OKTHAULAX PUGNAX ZONE. 49 



the last whorl by about 25 spiral threads with wider interspaces ; the 

 umbilicus is deep but narrow with its margin broadly rounded. The 

 pillar has two prominent plaits, and the aperture was probably 

 trigonal. The remaining portion of the shell is 9.5 mm. long with 

 a maximum diameter of 5 mm. It belongs to the section called 

 Sveltia by Jousseaume. 



Family OLIVIDAE. 



Genus OLIVA Martyn. 



Oliva Martyn, Univ. Conch., vol. 3, pi. Ill, 1786, First species, 0. corti- 

 cata Martyn. 



This genus is commonly attributed to Bruguiere, but was proposed 

 at least three years earlier by Martyn, as I showed in 1905.^ 



OLIVA POSTI, new species 



Plate 12, fig. 24. 



Shell small, solid, smooth, with 4 or more whorls; nucleus defec- 

 tive; suture moderately channeled; shell rather slender; last whorl 

 with a wash of callus near the suture; aperture long and narrow, 

 acute behind; outer lip slightly thickened, internally smooth; inner 

 lip plicate, in front as figured; canal deeply excavated. Height, 

 21.5 ; height of last whorl, 18 ; maximum diameter, 8.5 mm. 



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



Type-specimen from the Post collection, U. S. Nat. Mus., No. 

 165045. 



Genus OLIVELLA Swainson. 



Olivella Swainson, Zool. 111., vol. 2. pi. 58 and text, 1831. Tyi>e, Oliva dama 

 Mawe; Dall, U. S. Geol. Survey, Prof, paper No. 59, p. 31, 1909. 



OLIVELLA LATA Dall. 



Plate 15, fig. 4. 



Olivella lata Dall, Trans. Wagner Inst., vol. 3, pt. 1, p. 45. ]>1. 4, fig. 8&, 

 1890. 



Tampa silex beds, at Ballast Point, Tampa Bay, Florida, Shepard, 

 Dall, and Post. U. S. Nat. Mus., No. 165016. 



This is perhaps nearest some of the recent forms like 0. strigata 

 Eeeve, and 0. fuscocincta Dall from the West Indies, none of which, 

 however, are as broad and thin as O. lata. 



1 Proc. U. S. Nat. Mus., vol. 29, No. 1425, p. 428. 

 54907°— Bull. 90—15 i 



