FAUNA OF OETHAULAX PUGNAX ZONE. 41 



Height of shell 23, of last whorl 15, maximum diameter of shell 

 9 mm. 



Tampa silex beds, not rare. U. S. Nat. Miis. No. 166096. 



This species is near T. servata Conrad, also found in the same 

 horizon, but is more robust and has ten instead of only six axial 

 ribs. It grows larger than the dimensions above given, but the 

 description has been drawn from a more perfect if smaller specimen. 



DRILLIA OSTREARUM Stearns. 



Drillia ostrearum Stearns, Proc. Boston Soc. Nat. Hist., vol. 15, p. 22, 

 1872.— Dall, Proc. U. S. Nat. Mus., vol. 6, p. 328, 1883.— Tryon, Man 

 Conch., vol. 6, p. 197, pi. 34, fig. 79, 1884.— Dall, Trans. Wagner Inst., 

 vol. 3, pt. 1, p. 30, 1890. 



Oligocene of Alum Bluff, Chattahoochee River, and of the Tampa 

 silex beds, Tampa Bay, Florida; Pliocene of the Caloosahatchie 

 River, Florida: living from North Carolina south to Florida and 

 Yucatan between low-water mark and 15 fathoms. U. S. Nat. Mus. 

 No. 1122088. 



A species of this type occurs in practically every horizon from 

 the Eocene up. 



DRILLIA SELLA, new species. 



Plate 12, fig. 10. 



Shell small, slender, acute, solid, with nine whorls separated by a 

 closely appressed suture ; nucleus smooth, plump, of about one whorl ; 

 subsequent whorls strongly and sharply sculptured; axial sculpture 

 of (on the penultimate whorl nine) prominent rounded ribs, begin- 

 ning in front of the anal f asciole, continuing over the whorl, on the 

 spire to the suture, on the last whorl over the periphery, gradually 

 becoming obsolete on the base; the interspaces are about equal in 

 width to the ribs, and the incremental lines are not prominent ; spiral 

 sculpture behind the anal fasciole of a prominent keel close to the 

 suture; the fasciole being a strong smooth-surfaced constriction, in 

 front of which the ends of the ribs form a sort of shoulder to the 

 whorl; there are also (on the spire three, on the last whorl nine) 

 prominent spiral threads with wider interspaces which override the 

 ribs and are continuous between them; the suture is laid on the 

 fourth thread in front of the fasciole; anal sulcus shallow, rather 

 wide; aperture narrow, outer lip prominent in the middle, sharp- 

 edged, not varicose; inner lip raised, continuous over the body to 

 sutural commissure, smooth; pillar smooth, canal wide and deep. 

 Height 11.4, maximum diameter 3.7 mm. 



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

 specimen from the Post collection, U. S. Nat. Mus. No. 165035. 



