290 SPIROSTEMMA. 



Jamaica: Swift River head, St. George district of Port- 

 land parish (C. B. Adams). 



Cyl. princeps C. B. A. Contrib. no. 9, p. 167 (April, 1851). 

 PFR., Monogr., iii, p. 580; iv, 711; vi, 359; vii, 434. 



The largest species of the group, apparently distinct by 

 its flat whorls, strong basal keel, and projecting aperture. 

 The suture is seam-like, projecting rather than impressed, 

 the smooth keel visible above it. 



5. S. CARINATA (Pfeiffer). PL 35, figs. 50, 51. 



Shell slightly rimate, subcylindrical, tapering above, trun- 

 cate, obliquely striate, with a silken luster, fleshy-fulvous. 

 Whorls remaining 12, rather flattened, the last shortly free, 

 compressed-carinate at the base. Aperture oblique, oval, an- 

 gular at the base, the peristome shortly expanded through- 

 out. Length 22, diam. 4 mm.; aperture 4 mm. long, 3 wide 

 (P/r). 



Cyl. carinata PVR., P. Z. S., 1852, p. 68 ; Monogr., iii, p. 571. 

 SOWERBY, Conch. Icon., xx, pi. 8, f. 67. 



Habitat unknown (Mus. Cuming). 



The description and Sowerby's figure indicate a shell sim- 

 ilar to 8. princeps, but with a larger aperture and greater 

 diameter. 



6. S. INUSITATA (Vendryes). PI. 34a, figs. 1, 2. 



' ' Shell much elongated, cylindrical, rimate, somewhat shin- 

 ing and transparent, color light brown; spire slightly taper- 

 ing both above and below its greatest diameter, which is 

 about the middle; truncate with the loss of 7 to 8 whorls, 

 whorls remaining 11 to 12, planulate, shouldered by an early 

 obsolete angle, the last detached and descending, strongly 

 carinated at the base, the carina extending to the back of 

 the aperture; stride waved, strong and compact, crossing the 

 whorl obliquely and continued up to and many crossing over 

 the edge of the suture, which appears fringed here and 

 there by their intrusion; aperture like that of dunkeriana, 

 but rather larger in proportion to the shell, and less oblique 

 than in that species, well produced over the penult, whorl. 

 Height 18 mm., greatest breadth above the middle of the 



