240 new- york fauna — mollusca. 



Mya arenaria. 



PLATE XXX. FIG. 290. 



(STATE COLLECTION.) 



Mya armaria. Linn. Syst. Nat. p. 1112. Lam. An. sans vert. Ed. Brur. Vol. 2, p. 527. 

 M. mercenaria. Say, Journal Acad. Nat. Sciences, Vol. 2, p. 313. 

 M. armaria. Conrad, Amer. Mar. Conchology, p. 42, pi. 9. fig. 1. 

 M. id. Gould, Invertebrata of Mass. p. 40. 



Description. Shell transversely ovate, subequilateral, convex (but slightly more so in one 

 valve), gaping at both ends, but more so at the posterior ends, which are slightly curved 

 outwardly. Surface roughened, and antiquated by the different stages of growth. Beaks 

 small. Tooth in the left valve erect, spoon-shaped, with a grooved ridge on the back, pro- 

 jecting beyond the margin like another tooth ; between this and its corresponding cavity in 

 the other valve is a strong ligament. Palleal impression deeply notched behind. 



Color, chalky white or ferruginous ; epidermis dull brown. 



Vertical axis, 1*5 --2" 0; transverse ditto, S'O-S'O. 



This is one of our most abundant and useful species on the coast of New- York. It is 

 found every where, burrowed a few inches under the sand, between high and low-water 

 mark ; and is readily detected by a small aperture in the sand, through which it ejects a 

 stream of water upon treading hard on the sand in its neighborhood. It is known under the 

 various appellations of Long Clam and Piss Clam, to distinguish it from the common Round 

 Clam ( V. mercenaria). In some districts it still retains its ancient aboriginal appellation of 

 Maninose. It forms a very nutritious article of food ; and when properly cooked, is by many 

 equally prized with the oyster. On many parts of Long island, the hogs are accustomed to 

 root for this species, and follow the change of tides with unerring sagacity. There is a strongly 

 marked and constant variety found in our waters, which has the anterior longer than the pos- 

 terior margin ; the upper extremity is compressed, gaping and very much contorted, and 

 more gibbous than the typical form of the species. This variation has been attributed to its 

 locality among coarse gravel. 



(EXTRA-LIMITAL.) 



M. acuta. (Say, 1. cit. Vol. 2, p. 3 1 3.) Shell oblong-ovate, narrowed behind, rather strongly wrinkled : 

 posterior hinge and basal margins subequally arcuated ; tip of posterior margin equidistant from 

 the apex and middle of the base. Tooth moderate, with a small not prominent tooth on its pos- 

 terior side. Length, 1*5; width, 2 - 8. Considered by some writers as a variety of the prcceding # 

 Southern Coast. 



M. truncata. (Lin. Syst Nat. p. 1112. Gould, 1. c. p. 42. Pl. 29, fig. 289 of this book.) Shell 

 oblong-ovate, or subquadrate and truncated behind, where it gapes widely: basal margin irregu- 

 larly sinuous ; epidermis tough and corrugated ; tooth broader than long, with a slightly thickened 



