220 NEW-YORK FAUNA MOLLUSCA. 



posterior extremity slightly emarginate : cavity of the cartilage profound. Teeth large, prominent, 

 grooved. Muscular impressions very large ; inner margin regularly crenulated. Length, 5-0- 

 6*0. Allied to prmparca, and larger than mercenaria. Coast of North and South-Carolina. 

 V. fluctuosa. (Gould, Inv. Mass. p. 87, fig. 50.) Shell moderately small, transversely ovate, lenti- 

 cular, rather thin. Surface with 20 - 25 recurved concentric waves, vanishing at the side; areola 

 none. Middle tooth in each valve cleft. Color: epidermis thin, glossy, yellowish; beneath this, 

 white. Length, 0-8; height, 0-6; breadth, 0-22. 



GENUS ASTARTE. Sowerby. 



Animal unknown, but presumed to resemble that of Venus. Shell rounded, subequilateral, 

 compressed, thick. Hinge with two strong diverging cardinal 166111 on one valve, and two 

 very unequal ones on the other, or only one large one ; palleal impression simple ; ligament 

 exterior. 



ASTARTE CASTANEA. 

 PLATE XXVIII. FIG. 280. 



(STATE COLLECTION.) 



Venus casianea. Say, Journ. Acad. Nat. Sc. V. 4, p. 273. 



Astarte id. Id. American Conchology, pi. 1. Totten, Am. Jour. Vol. 28, p. 3-18, fig. 2. 



Crassina id. Conrad, Mar. Conch, p. 72, pi. 17, fig. 3. Russel, Essex Jour. Vol. p. 57. 



Astarte id. Gould, Invertebrata of Mass. p. 7C, fig. 45. 



Description. Shell thick and heavy, suborbicular or subtrigonal, with prominent and nearly 

 central beaks, much more elongated than in the following species. Surface with minute 

 concentric wrinkles and larger waves, with faint traces of radiating lines. Area in front of 

 the beaks very deeply excavated, short, broad and smooth : posterior slope almost straight, 

 with a long narrow lanceolate depression. Hinge solid ; the margin very broad, with one 

 stout tooth with a pit on each side in one valve, and two somewhat diverging teeth in the 

 other, with a cavity between them to receive the opposite tooth. Palleal impression without 

 a sinus : basal margin crenulated within. 



Color. Epidermis chesnut-brown, occasionally deep mahogany with darker and paler zones ; 

 posterior margin blackish : foot of the animal vermilion. 



Vertical axis, 1*0 — 1*2; transverse ditto, 1"0-1'2. Diameter, 0*5. 



Var. a. picea. With a few wrinkles without waves, large and solid; epidermis dark tar- 

 colored (Gould). 

 Var. b. procera. Lighter colored ; vertical axis longest (Totten). 



This species occurs along the coast of Long island, on the outer bars generally, although 

 it has been dredged within the harbors. 



