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Show 1881] MR. E. A. SMITH ON THE GENUS GOULDIA. 491 modesta are small forms of the genus Crassatella. Gouldia minima, cerina, australis, and perhaps dilecta, which I only know from description, prove to belong to Circe; and G. lamellosu is unknown to me. Of the former group, four species, viz. guadeloupensis, parva, mactracea, and pfeifferi, are, I believe, one and the same shell, and may retain d'Orbigny's name, which was the first published. In conclusion I will add the description of a small species of Crassatella from the west coast of Africa. CRASSATELLA KNOCKERI, sp. nov. Shell small, transparent whitish, angular at the beaks, rounded on the ventral margins, compressed, a little inequilateral, concentrically ribbed. Ribs strong, terminating anteriorly at the narrow shallow lunule, and posteriorly defining a very narrow linear dorsal area separated by deep sulci rather broader than the ridges. Umbones small, smooth, hyaline, approximated; anterior and hinder dorsal slopes subequal, the former feebly concave, the latter rectilinear. Hinge consisting of two cardinal teeth in the right valve, the anterior one very conspicuous, the other very small; and two in the left of more equal size. Lateral teeth elongate, one on the posterior slope of the right valve, fitting into a corresponding groove in the left, and one on the anterior slope of the latter received by a groove in the right. Ligament placed in a cavity immediately posterior to the two cardinal teeth of the left valve, and between those of the right. Interior of valves glossy, exhibiting the external ribbing, owing to their transparency, prettily crenulated within along the ventral margin. Length from umbo to opposite margin 4^ millim., width 41, diam. 1£. Hab. Whydah, West Africa (dredged by Captain Knocker, R.N.). Although of small size, this pretty shell appears to be adult; and the crenulated inner edge of the valves indicates maturity. Its transparent texture is peculiar; and it is very stoutly costate for so small a species. May 3, 1881. Professor Flower, LL.D., F.R.S., President, in the Chair. The following papers were read :- 32* |