"5 ^ E ade. " 
162 Couthouy's me: on 
indistinct on the left, extends obliquely from the beaks 
to the lower angle of the posterior extremity. The 
beaks moderately prominent, and inclining a little back- 
wards, exhibit a singular appearance, the anterior por- 
tion of their summits having the outer coat or layer of 
calcareous matter, as it were perpendicularly cut through, 
projecting a little over the posterior side (which is some- 
what pearly); and terminating in a sharp angle. Ex- 
ternally, the shell presents very numerous fine, but dis- 
tinct incremental lines, and is covered with a thin, ad- 
herent, light-brown epidermis, most apparent near the 
margins. Viewed under a lens, the external surface is. 
seen to be covered with very minute, irregularly disposed 
granulations, similar to, but much finer and closer than 
those observed upon the Thracie. Seen in profile the 
outline is sinuous, the extremities of the shell being in- 
flected in opposite directions. . That portion of the in- 
terior, within the muscular and palleal impressions, is of 
a dull, unpolished. white, except in the cavity f | by 
the beaks, where, like the remainder, it exhibits a 
pearly lustre. The muscular impressions are rather su- 
perficial, the anterior is near the cardinal edge, long and 
narrow, the posterior remote, small and rounded; pid 
impression deeply. excavated posteriorly. 
Length twenty-fowr-twentieths, height sixteen-twen- . 
tieths, diameter ten-twentieths of an inch. 
Inhabits the coast of Brazil, on the statement of the 
person who brought. the shell hither. 
Ossenvartons. . This very singular shell is the only 
species yet known of the genus. The error committed 
by M.. de Blainville, in confounding it. with genus 
