268 GINGLYMACONCHA. MYADZ&. 
STIRPS I. 
Hinge toothless; the horizontal process which bears the 
elastic opening ligament is in the left valve. 
Genus 16. Mya. 
The shells rather thick, the left valve rather larger than the 
right valve ; the umbones are central ; the process bearing the 
closing ligament is fixed, horizontal, and excavated above. The 
foot is small, and abruptly conically compressed ; the lips are 
elongated and acuminated ; the branchie or gills are free 
behind. 
The Mye live beneath mud, sand or shingles in most of our 
estuaries, but are most frequently found in the open pure sea. 
The respiratory tube varies extremely in different individuals 
of the same species, and depends on the depth of their habita- 
tions, which they are unable to change; their foot being too 
small for much, if any locomotion. 
1. MYA ARENARIA. 
Shells compressed, ovate, acuminated posteriorly, sculptured 
with irregular concentric striee ; the valves equally convex ; the 
epidermis yellowish or rufous brown, most frequently more or 
less spotted with blackish. Length five inches; height two 
and a half or three inches. 
Mya arenaria, Lister, Conch. t. eccexix. f. 263; Linn. Faun. 
Suec. 2125; Syst. Nat. 1112; Penn. Brit. Zool. iv. 79. 
t.xln.; O. Fabr. Faun. Gren. 405. no. 407 ; Chem. Conch. 
vi. 3. Vig., and t.i. f. 3, 5; Pult. Cat. Dorset. t. iv. f. 8; 
Brug. Encycl. Méthod. t. eexxix. f. 1. a, b.; Donov. Brit. 
Shells, t. xxxv.; Mont. Test. Brit. 30; M. §& R. Trans. 
Linn. Soc. vi. 36; Lam. Hist. Nat. des Anim. sans Vert, 
v. 461; Flem. Edinb. Encycl. vii.; Dill. Desc. Cat. 41; 
Turt. Conch. Dict. 98. 
Chama arenaria, Da Costa, Brit. Conch. 232. 
It is often sent to market as food, and is popularly denomi- 
