CLEIDOTILERUS, a genus of Acephalons Nollusea (Conchifera of Lamarck), established by 31r. Samuel Stutehbury for a testae-eons animal, the mechanism of whose bingo connecting the two valves differs most materially from that exhibited by other Bivalves.
Shell bivalve, somewhat pearly, inequivalve, involute, attached by the outside of the larger valve. Hinge with a small conical pointed tooth iu the free valve, fitting into a corresponding pit in the attached valve. A testaceous rather elongated curved appendage, connected by cartilage, is inserted into a deep cicatrix within each umbo ; inns cular impressions, two in each valve, lateral : the anterior ligulate ; the posterior suborbicnlar. Muscular impression of the mantle entire. Ligament external. (Stutchbury. modified by G. B. Sowerby.) M. De Roissy had separated the genus from Marna, with which it might be easily confounded by a superficial observer under the name of Chamostrea ; but he does not seem to have been aware of the appendage, and, as Mr. Stutehbury observes, his name is entirely inap plicable, there being nothing in the shell to connect it with Oetrea.
CleidothaTus Chamoides (Stutchbury). Shell involute, brownish internally of a greenish pearly lustre, attached by the anterior side of the right valve, which is of great depth ; left valve but slightly convex ; the clavicular appendage with a groove on the convex side.
Mr. Stutehbury states that C. Chamoides was found attached to sandstone rocks by T. Young, Esq., It.N., together with an Asper gillum (perhaps Ayglutinans of Lamarck), some Genera, &c., while searching near the entrance of Port Jackson, pointed out to him as the spot where Mr. Stutchbury discovered in 1S26 the first living Mirage/hr. In general contour this shell has so great a similitude to Chama, that, without opening it, there would be no hesitation in pronouncing it to belong to that genus. [Ctrastacea.] Mr. G. B. Sowerby is of opinion that, as far as the character of the internal hinge cartilage having an elongated testeccous appendage gore, Cleidothams connects the Mona. of Lamarck with his Tlyaires.