a2 CATALOGUE OF PHANEROPNEUMONA. 
convex, the last one rounded, deeply excavate beneath, forming 
a kind of umbilicus; aperture perpendicular, broad, semioval ; 
peristome continuous, simple, somewhat reflected, with the right 
margin arcuately dilated, columellar margin scarcely detached, 
basal margin continued into a small lamina. Height 3, greatest 
breadth 2!, least br. 13 mill. 
Stoastoma Cumingianum, Adams, Mon. p.9; Pfr. in Z. f. UM. 1850, 
p. 62; Pneum. Mon. p. 324. 
Hab. Jamaica. 
12. Sroastoma PETITIANUM. 
Shell between globose and discoidal, dingy white, with eight or 
ten raised slender spiral lines, of which three or four are visible 
on the spire, and as many others, which are more minute; spire 
moderately elevated, convex; whorls 34, moderately convex, 
with a lightly-impressed suture; last whorl very rounded ; 
aperture much contracted behind the labrum, which is but 
moderately produced, and is double, with the outer margin 
scarcely modified by the larger spiral lines; labium moderately 
detached from the penultimate whorl; umbilicus rather small, 
with the spiral lamella but moderately developed. Height 0.04, 
greatest breadth 0.06, least br. 0.05 inch. 
Stoastoma Petitianum, Adams, in Ann. Lye. New York, v.n. 2, 
p. 67; Contrib. to Conch. n. 8, p. 151; Pfr. Pneum. Mon. p. 324. 
Hab. Jamaica. 
13. StoastomaA ANTHONIANUM. 
This shell is like the preceding, but the spire is much depressed, 
the spiral lines are rather stronger, and the aperture is very 
campanulate, the labrum being very much produced before the 
deep constriction. Height 0.035, greatest breadth 0.07, least 
br. 0.055 inch. (Adams.) 
Stoastoma Anthonianum, Adams, Contrib. to Conch. n. 8, p. 151; 
Pfr. Pneum. Mon. p. 325. 
Hab. Jamaica. 
§ 4. Shell striated, discoidal. 
14. Stoastoma GouULDIANUM. B. M. 
Shell umbilicate, discoidal, thin, pellucid, greenish-glassy, sculp- 
tured with distant sharp spiral keels and very minute lines; spire 
rather flat, with a very minutely raised apex; whorls 33, con- 
vex, the last one broad, depressed; aperture nearly perpen- 
dicular, rather triangular; peristome simple, sharp, continuous, 
with the right margin scolloped angularly, much produced 
