120 GEOLOGY AND PALEONTOLOGY OF THE WEST INDIES. 



not far removed from the ancestral stock of the smooth Antillean species of 

 Hemisinus. 



"There is, of course, a possibility that this Antigua species belongs to the 

 genus Pachycheilus, which is represented in the recent fauna of Cuba by P. 

 conicus (Orb.) and P. violaceus Prest.; but the straighter columella does not, 

 in our opinion, favor this view. 



"The type has lost the shell from the spire by conversion into flint, but the 

 surface has been preserved in perfection on the last whorl." 



Locality. Dry Hill Point, Antigua, station 6867, Vaughan. 



Geologic horizon. Oligocene. 



Type. Philadelphia Academy. 



Figured specimen. U. S. Nat. Mus. No. 166998. 



Turritella anguillana, new species. 

 (Plate 4, Figures 1, 2, 3.) 



The following is a description of this species: 



Shell long, slender; whorls medially constricted, with two prominent spiral 

 cords on the anterior quarter, the cord adjacent to the suture usually the 

 smaller; remainder of the whorl with fine spiral threads; finer details of sculp- 

 ture obliterated on specimens at hand. 



A fragment of 4 whorls tapers from 11.5 to 8 mm. in 25.5 mm. length. 



This species appears to be intermediate between T. mississippiensis 

 Conrad from Vicksburg and T. systoliata Dall from the Tampa silex 

 bed, resembling the former in that the posterior of the two prominent 

 cords is the larger, and resembling the latter in the constriction of the 

 whorls. 



T. anguillana is closely related to T. halensis Dall from Bainbridge, 

 but in T. halensis the constriction is limited to the middle third of the 

 whorl. 



Locality. Crocus Bay, Anguilla, station 6894, Vaughan. 



Geologic horizon. Oligocene. 



Type.U. S. Nat. Mus. No. 167008. 



Turritella dubiosa, new species. 

 (Plate 4, Figure 4.) 



The following is a description of this species: 



Shell conic, rapidly expanding; whorls nearly flat or very slightly convex, 

 with a low, sharp, spiral thread at the anterior quarter and a finer thread 

 adjacent to the suture; median portion smooth; posterior third with two or 

 more low, spiral threads; suture very little impressed. 



Length of fragment of about 5 whorls, 26 mm. , 



This species is represented in the collection by a single slightly 

 crushed fragment. The figure is from a photograph of the broader side. 

 Locality. Crocus Bay, Anguilla, station 6965, Vaughan. 

 Geologic horizon. Oligocene. 

 Type.U. S. Nat. Mus. No. 167009. 



