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rounded, the latter somewhat more obtusely so : basal margin 
regularly rounded, without any undulation before : apex obtuse, 
but little prominent : cardinal teeth two : fosset dilated fusiform, 
abruptly very narrow at the beaks : lateral teeth none : posterior 
muscular impression very slender, and elongated. 
This species is more transverse than usual in this genus ; it is 
altogether destitute of lateral teeth, and the posterior muscular 
impression is remarkably slender. It is superior in point of size to 
either the orhiculatum, or radiatumy nob., though proportionally 
somewhat thinner. I obtained a specimen on the coast of Gleorgia 
that is somewhat worn ; its color is whitish, a little tinged with 
yellowish. PL 28 ; middle figures. 
Amphidesma uEQUALE. — Specific character. Left valve with 
remote grooves instead of lateral teeth. 
Ampliidesma sequale, nobis. Jour. Acad. Nat. Sci., vol. 2, p. 
307, 
Ohs. — This is allied to A. tenue and Boysii, Montagu, of the coast 
of England, of which, however, I have not any good description or 
specimen to compare, and it may possibly prove to be the same with 
one of these, when comparison shall be made. 
Since my quoted description was given, many specimens have 
been found on the coast of Charleston, for which I am indebted to 
the late Mr. Stephen Elliott. 
It belongs to the genus Ahra of Leach. PL 28 ; four exterior 
figures. 
Fuses. — Shell univalve, spiral, fusiform, canaliculated at base, 
covered with an epidermis, and destitute of varices ; spire elevated ; 
aperture oval ; columella simple ; labrum on its edge simple ; oper- 
culum horny, subconcentric. 
Ohs. — This genus was separated from the Linnman Murex by 
Bruguieres, who, however, included Pyrula, Fasciolaria, Fulgury 
and Pleurotomay which have since been withdrawn from it by La- 
marck and Montfort. The latter author distinguished another 
genus by the name of Latirusy for the umbilicated species. Not- 
withstanding these improvements, it is still acknowledged to be 
an artificial assemblage, and more divisions must therefore be made. 
Lamarck places the genus in his family of Canaliferes ; from all 
the genera of which it is distinguished by very obvious characters, 
excepting Pyrulay which, however, consists of thin, more or less 
