290 Dr. Gould’s Descriptions of Shells 
composed of about six convex whorls. The columella is thick, 
and somewhat raised above the surface of the last whorl. 
' This shell I obtained, together with the Pholas semicostata. 
It differs essentially from all its congeners on this coast. 
Perhaps the Cingula aculeus, Gould, is its nearest analogue, 
but there can be no danger of their being confounded. 
ART. XIX. DESCRIPTIONS OF SHELLS FROM THE COAST OF 
AFRICA. By AvcvsTus A. Goutp, M. D. Read April 23, 1845. 
Tue following shells, with many other fine specimens of 
rare species, were collected by Charles J. Bates, Esq., As 
sistant Surgeon, United States Navy, and by his permission I 
offer the following descriptions. The Pholas were found 
living, and imbedded in lime stone. The others, with two 
fine species of Tellina, a Cytherea probably new, and a 
Sigaretus were brought up, at one time, by the anchor; = 
* "e locality I have failed to remember. : 
Pnuornas Brancuiata. Pl. XXIV. Fig. 7. 
,Strucetà: dorso secutis tribus obtecto, unico magno umb 
duobus marginalibus lanceolatis, duobus quoque ventralibus ; apo 
exili, flexuoso-falciformi. : 
Long. 11; lat. 2 poll. 
Shell egg-shaped, posteriorly pointed, rather solid, of a 
dingy white color, its surface divided into three nearly 
triangular areas; the anterior one is largest, and its v 
portion is sculptured by close, concentric, finely Serra 
striæ, while beneath it is smooth and polished ; the middle 
sarea is marked by very fine transverse strize ; and the ot 
rior one is remarkable for a series of concentric, horny, shining, 
flexible lamine, resembling the branchize of some c ry 
The back is protected by a very large, rounded, firm we 
