14 
DESCRIPTION OF SPECIES. 
edges are rounded. The sutures between the whirls are not very deep. 
Aperture, rather small, hut not contracted within. The central 
tooth is prominent and long, extending hack into the shell .18, and 
its position is central; the upper tooth is placed just above it, and al- 
though it is not prominent, is long, and takes a turn around the column. 
The margin is not produced forward quite as far as the diameter 
of the shell; it is not greatly thickened, measuring .06, and the posterior 
portion is produced backward into a thin, though not prominent edge. 
The frontal bar is moderately developed, and the striations are inter- 
rupted, not appearing within it. The striations on the back of the shell 
may be seen within the aperture, when held against the light. The ani- 
mal is not very large; eye peduncles, .15 long; tentacles, .05; jaw, as in 
S. copia. 
Color, white, with an occasional spot of purplish between the stri- 
ations, and with the apex flesh color; internally, purplish brown which 
fades as it approaches the teeth, and does not extend beyond them; thus 
both they and the portions beyond them are pale flesh color. Color of 
animal, pale brown, with a Y-shaped mark on the back, of the same 
color but somewhat darker. 
DIMENSIONS. 
Sizes of types, .90 by .40 and .88 by .40. Largest specimen, 1.04 
by .44. smallest, .82 by .40. Greatest diameter, .47; smallest, .38. 
Longest specimen, 1.04; shortest, .82. 
OBSERVATIONS. 
Although the great majority of specimens of this species, are con- 
stant to the type, yet variation is very great, some specimens before me 
ranging from cylindrical, with the three first whirls of the same size, to 
those that are nearly top-shaped, having the first whirl the largest, with 
all gradation between. The margin varies in thickness, .12 being the 
extreme width. In color the tendency is to become whiter than the 
type, with no spottings and no fleshy tintings on the apex. The whirls 
are almost invariably ten but are rarely eleven. The striations vary 
from 16 to 19, but in all of this variation, the only decided form, is one 
that lives on stunted vegetation which is found in exposed situations on 
rocks; these are white with aheavy shell, through which the striations 
cannot be seen when held to the light. Some shells are not long but 
quite thick in diameter when compared with the t}^pe. 
The Small Rough Strophia is found on the low vegetation that 
grows on the margin of the beach on the south side of Little Cayman, 
