HELICINIDS. 233 
above, basal margin dilated and expanded; lower angle con-~ 
tinued into a lamina, which is scarcely raised. Height 1, 
greatest breadth 3, least br. 2} mill. 
Stoastoma Gouldianum, Adams, Mon. p.5; Pfr. in Z. f. I. 1850, 
p- 62; Pneum. Mon. p. 325. 
Hab. Jamaica. 
15. Sroastoma TAPPANIANUM. 
Shell subdiscoidal, pale horn-colour, subtransparent, with seven 
spiral carine, of which the upper one is small and the lower 
one very minute, and of which two are visible on the upper 
whorls; with very delicate spiral raised lines, usually one between 
the first pair of carinz and two or three in each following inter- 
space; spire moderately and convexly elevated; whorls 33, 
moderately convex, with a deep suture ; last whorl scarcely de- 
tached from the penultimate whorl near the aperture ; aperture 
rather more than a semicircle, a little contracted behind the 
labrum, which is well produced, above rather abruptly produced, 
scarcely modified by the carinz; labium much detached from 
the penultimate whorl and a little reflected; umbilicus rather 
wide, with the spiral lamella moderately developed. Opere. 
very deeply concave externally, smooth, auriculate at both ex- 
tremities. Height 0.045, greatest breadth 0.086, least br. 0.07 
inch, 
Stoastoma Tappanianum, Adams, in Ann. Lyc. New York, v. n. 2, 
p- 65; Contrib. to Conch. n. 8, p. 149; Pfr. Pneum. Mon. p. 325. 
Hab. Jamaica. 
16. StoastomaA VILKINSONIA. B. M. 
Shell subdiscoidal, pale horn-colour, subtransparent, with five 
spiral carine, of which one runs into the suture, and one ap- 
pears on the middle o fthe whorls of the spire; some have, in 
place of the last one, two smaller carine; with very delicate 
spiral raised lines, usually four to six in each interspace; spire 
moderately and convexly elevated; whorls 3$, angulated, with 
a deep suture; last whorl rather large, detached from the 
penultimate whorl near the aperture; aperture campanulate; 
labrum produced very far, above abruptly produced and au- 
riculate, with wide and deep scallops formed by the produced 
carine ; labium much detached from the penultimate whorl and 
a little reflected ; umbilicus rather wide, with the spiral lamella 
moderately developed. Operc. very deeply concave, auriculate 
at both extremities, very firmly punctulate. Height 0.035, 
greatest breadth 0.07, least br. 0.055 inch. 
x 2 
