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of the shell ; labium in the middle concave, with about two obso- 
lete striae, and a more profound one at base. 
Length seventeen-twentieths ; breadth nearly nine-twentieths of 
an inch. 
In the collection of the Academy is a shell from the West 
Indies, to which our species is very closely allied ; and although 
the striae of the labrum are double in the former, yet it is probable 
that the two shells will be found to constitute one species, when 
more specimens are examined and carefully compared. In the 
systems it will probably arrange near to W vulgatum. 
For this shell I am indebted to Mr. Stephen Elliott, of Charles- 
ton. 
Nassa alba.— -Shell ovate, white, immaculate, longitudinally 
ribbed or undulated, and with spiral striae ; ribs equal, equidistant, 
symmetrical, from ten to eighteen on the body whorl ; striae equal, 
equidistant, filiform, elevated as distinctly upon the ribs as in their 
interstices, and from seventeen to twenty in number on the body 
whorl ; whorls seven, convex ; suture deeply indented ; aperture 
suborbicular ; labrum with a larger rib than the others on the ex- 
terior, and striate within ; labium, plate distinct, entire, but not 
expanded, with an indented line near the base, and a prominent one 
near the junction with the labrum. 
Length nine-twentieths ) breadth three-tenths of an inch. 
Inhabits the southern coast of East Florida, and the West India 
Islands. 
I owe this beautifully sculptured shell to the politeness of Mr. 
Elliott. It seems to be more closely allied to N. macula of 
authors than to any other with which I am acquainted. It is, 
however, distinguished as a species by its more ventricose form, by 
its ribs being more rectilinear, and by the spiral striae being more 
prominent and distinct. Those found on the coast of Florida are 
in no respect different from specimens brought from the W est 
India Islands. 
Nassa lunata. — Shell reddish-brown, with about six volu- 
• tions ) whorls with two revolving lines of dilated, sublunate, whitish 
spots, and sometimes a third one at base ; suture not deeply im- 
* pressed ; labrum dentate on the inner submargin, the superior teeth 
more prominent ; labium with the plate not thickened. 
