This and A. oblonga are the only species I am yet acquainted with, whose form is not globose. It never grows to a size much larger than the figure; the whole shell is marked by fine longitudinal striæ, and transverse lines of minute dots, discernible only by the aid of a common magnifier; the aperture within is brownish flesh-colour; the margin is strong and reddish, and, within that of the outer lip, is a thickened rim; which, should the operculum be testaceous, may supply the place of the groove for its reception observable in A. globosa and corrugata. The localities of both these species are unknown to me.
EBURNA Valentiana,
Arabian Eburna.
Generic Character.
Testa turrita, lævis, nitida, umbilicata, basi truncatâ, emarginatâ. Aperturæ angulus superior internè canaliculatus. Animal marinum.
Shell turrited, smooth, polished, umbilicated, base truncated, emarginate. Upper angle of the aperture with an internal channel. Animal marine.