90 BRACHYPODELLA, JAMAICAN. 



aa. Dextral. 



b. Diam. about 3.5 mm. ; basal keel short. 

 B. pearmanceana, no. 47; B. alabastrwa, 

 no. 46. 

 bb. Diam. 2 to 2.7 mm. ; basal keel long. 



B. alba, no. 48. 



3. Shell cylindric-tapering, white, densely obliquely 

 striate, the whorls convex, oblique, the last not free, 

 carinate below only ; aperture longer than wide ; axis 

 very slender, sinuous in the later whorls. Section 

 Apoma. 



a. Length 21-30, diam. 4.5 mm. 



B. chemnitziana, no. 49. 



aa. Length 19-31, diam. 3.3-4 mm., thus more 

 slender. B. gracilis, no. 50. 



Section Geoscala Pils. & Van., 1898. 



Proc. A. N. S. Phila,, 1898, pp. 272, 279. Type B. seminuda. 



Shell small, cylindric or fusiform, sculptured with contin- 

 uous or interrupted ribs, the last whorl more or less free, the 

 neck strongly carinate below, roundly angular peripherally; 

 aperture rounded; axis slender and straight; apical whorl 

 high. Type B. seminuda. 



Radula intermediate between that of Brachypodella s.s. 

 and that of Mychostoma. The cusp of the central is moder- 

 ately wide; the inner lateral has a very small, peg-like eeto- 

 cone; the outer lateral and the marginals are like those of 

 Mychostoma (pi. 10, fig. 18, B. seminuda, Clarendon Park). 



Geoscala differs from Simplicervix by its strong sculpture 

 and basal keel. It stands very close to the typical group of 

 Brachypodella, but differs by the very weak development of 

 the ectocone of the inner lateral tooth and the less expanded 

 cusp of the central. 



38. B. COSTULATA (C. B. Adams). PL 5, fig. 43. 



" Shell subovate, but elongated; whitish; with thin, very 

 prominent, very distant, moderately oblique ribs, of which 



