BEACH YPODELLA, JAMAICAN. 91 



there are about ten on the penult, whorl, and which, as usual 

 in this genus, are more crowded on the last whorl anteriorly 

 with a prominent but not sharp carina; spire with convex 

 outlines along the middle ; apex truncate, with the loss of five 

 or six whorls; nine or ten whorls remaining, rather flattened, 

 but with a deep suture; last whorl much detached and pro- 

 duced, angulated on the right; aperture much dilated on the 

 right, anteriorly a little angular, the rest rounded; lip some- 

 what thickened, rather narrow and sharp, reflected into the 

 plane of the aperture " (Ad.). 



Length 6.25, diam. 1.9 mm. ; length of an entire specimen 

 8 mm. (C. B. Ad.). 



Length 6.6, diam. 1.8 mm., whorls 8. 



Jamaica: interior of the western half. Whitney, Claren- 

 don; Troy and Balaclava, St. Elizabeth ( Jarvis) ; Mande- 

 ville, Manchester, and Montpelier, St. James (Henderson). 

 Also reported from Bellevue, St. Andrew (Gloyne). 



Cyl. costulata C. B. AD., Contrib. to Conch., no. 2, p. 20 

 (4), Oct., 1849. PFR., Monogr., iii, p. 574. SOWERBY, C. 

 Icon., xx, pi. 12, f. 104 (bad). GLOYNE, Journ. de Conch., 

 1872, p. 35. 



The whorls are most convex just below the suture. In some 

 specimens from Mandeville, coll. J. B. Henderson, the ribs 

 are weak, almost obsolete on the last two whorls, reappearing 

 on the neck, where they are almost interrupted in the con- 

 cavity above the keel. Figure 43 represents a specimen from 

 Whitney, Clarendon. 



39. B. ROBERTSI (C. B. Adams). PI. 5, figs. 45, 46. 



' ' Shell elongate, fusiform, widest a little below the middle : 

 pearl white : with, on each side of the suture, a series of very 

 transverse, prominent ribs, which abruptly terminate so as 

 to leave a large portion of the middle of the whorls smooth; 

 ribs about fifteen on each whorl; the series below the suture 

 being the larger; both series are continued on the two angles 

 of the produced part of the last whorl, over on the back part 

 of which each rib is united to its opposite by a small lamella ; 

 spire with the outlines quite convex except in the upper 



