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posterior cardinal tooth situated immediately under, and parallel to, 

 the edge of the lunule in the right valve, and a recipient cavity in 

 the left valve, similarly situated. Cyprina was separated, from the 

 circumstance of having an anterior, lateral, remote tooth. Vene- 

 nipia is very closely allied to Venus ; but the cardinal teeth are 

 parallel, and not divergent as in Venus ; they have the habit of 

 perforating and residing in limestone rocks. Sowerby has changed 

 the name of Venerupk and united to it several transverse species 

 of Venus, such as papilionacea, Itterata, &c., some of which, or 

 perhaps all, might enter Schumacher's genus Tapis. Several other 

 genera have been separated from the Linnajan Venus, such as 

 Calista and Arthemis of Poli ; Artliemis, Loripes and Meretrix of 

 Ocken ; Orbicuhis, Trigonia, Chione and Tapes of Megerle, and 

 others by Schumacher, but as we are unacquainted with the char- 

 acters of several of these we cannot estimate their relative value, 

 though we readily assent to the necessity of a reform in this 

 numerous and somewhat artificial group. 



The animal of Venus has the foot rather large and compre ssed ; 

 the mantle is undulated and furnished with a series of cirri ; the 

 tubes are moderately long and united ; mouth small, semi-lunar ; 

 branchiae not united, broad and short. Lamarck described eighty- 

 eight recent species and six fossil ones, and Blainville states that 

 Defrance announces forty fossil species. 



One of the most useful of our shells, the Clam, ( V. mercenaria, 

 Linn.,) belongs to this genus, but Schumacher has separated it 

 under the generic name of Mercenaria. It is the shell of which 

 our aborigines, with much persevering labor, formed their wam- 

 pum beads which they valued so highly, and which they strung 

 together in the form of belts and other ornaments. 



Venus grata. — Specific character. Granulated with longitu- 

 dinal and transverse striae ; whitish, with dotted rays of pale fer- 

 ruginous and blackish ; blackish oblique lines before. 



Desc. Shell transversely suboval, convex, with very numerous, 

 close set, longitudinal striae ; those on the anterior two-thirds of 

 the shell have a slight appearance of folds, or as if each one origi- 

 V nated beneath the one posterior to it in a somewhat imbricated 

 manner ; these striae are granulated by very numerous transverse 

 striae, which are more obvious on the posterior third of the shell, 

 and almost obsolete on the middle : color whitish, somewhat 



