HELICINID SH. 231 
’ blunt; whorls 5, rather flattened, the last one somewhat de- 
pressed, shortly detached anteriorly, excavated beneath; aper- 
ture semicircular; peristome simple, straight, with the right 
margin arcuately produced, basal margin continued into a keel, 
which ascends arcuately on the umbilical region. Height 2, 
greatest breadth 34, least br. 2? mill. 
Stoastoma Pfeifferianum, Adams, Mon. p. 8; Pfr. in Z. f. M. 1850, 
p. 61; Prneum. Don. p. 323. 
Hab. Jamaica. 
9. Sroastoma FADYENIANUM. B. M. 
Shell perforate, conoidally-depressed, thin, rather opaque, brown- 
ish-yellowish, sculptured with unequal and inequidistant spiral 
lines; spire raised in the middle into a small acuminated pin; 
whorls 42, scarcely convex, the last one depressed, rather angu- 
lated above, flattened beneath and deeply excavated in the 
centre; aperture perpendicular, rather larger than a semicircle; 
peristome simple, continuous, free, with the right margin scarcely 
dilated, basal margin acutely auriculated, continued into aspirally 
entering keel. Height 13, greatest breadth 3, least br. 24 mill. 
Stoastoma Fadyenianum, Adams, Mon. p. 7; Pfr. in Z.f M. 
1850, p. 61; Pneum. Don. p. 328. 
Hab. Jamaica. 
10. Stoastoma CHITTYANUM. B. M. 
Shell subumbilicate, somewhat conoidally-depressed, with crowded 
minute ridges, rather opaque, pale horn or wax-coloured ; spire 
conoidal, rather pointed; whorls 44, nearly flat, the last one 
rather rounded, detached anteriorly, flattened beneath ; aperture 
perpendicular, semioval; peristome simple, thin, with the right 
margin strongly arcuate, columellar margin straight; basal 
angle obsolete, produced into a broad lamina, which generally 
covers the very narrow umbilicus. Height 13, greatest breadth 
23, least br. 2 mill. 
Stoastoma Chittyanum, Adams, Mon. p. 10; Pfr. in Z. f. IL. 1850, 
p- 62; Pneum. Mon. p. 323. 
Hab. Jamaica. 
11. Sroastoma CUMINGIANUM. 
Shell subumbilicate, depressed, thin, with crowded spiral ridges, 
rather diaphanous, reddish or pale brownish; spire shortly and 
conoidally elevated, rather blunt ; whorls not quite 4, moderately 
