TRIBE MYARIA. 19 
Grycrmmeris Sirieva. Lam. 1.—Bl. t. 80. f. 3.— Reeve. t 
28.—Sow. G.—Mya Sinieua. D.p. 49.—Ch. f. 1934. Mya 
Picea. W.t. 2. f. 10. Thick, strong, oblong, covered with a 
black friable epidermis and generally decorticated about the beaks ; 
within, bluish white. 1.. 13.—Nenfoundland. The valves are 
often internally filled with a deposition of extraneous shelly matter.® 
G. Epentuta. Lich. Zool. Spec.—Mya E. Pallas Itin. no. 
93.—D. p. 48.— Wood, G. C. p. 96. Equivalve, oval, with a large 
hiatus, white, somewhat grooved transversely, and marked with 
about 33 striz on each valve, which are more distant at the narrower 
than at the broader end ; hinge edentulous, with a thick reflected 
lip. . 1 long.— Caspian Sea? 
TRIBE MYARTIA. 
Shells having a broad spoon-like tooth in each valve, or in one 
only ; gaping at both extremities, or only at one end: ligament 
internal. 
MYA. 
Transverse, gaping at both ends, with one large dilated projecting 
rounded and nearly vertical cardinal tooth in the left valve, and 
with a hollow in the opposite valve: ligament internal, short, 
thick and inserted in the hollow of the primary tooth, and in the 
pit of the other valve. 
M. Truncarta.* Lin. 1111.—D. p. 42.—Lam.1.—Ch. f. 1, 
2.—Don. t. 92.— Pen. 4. p. 78. t. 41. f. 14.—Turt. B. p. 31.— 
Mont. p. 32.—List. t. 428.—W. t. 2. f. 1. Ovate, ventricose, 
coarse, truncated at the anterior end, posteriorly rounded, ventral 
margin nearly straight ; white, covered by a brownish-yellow tough 
wrinkled epidermis, concentrically be gear tooth round, obtuse, 
entire, and projecting forwards. 2.. 23 1 —N. Lurope. 4 
M. Arenaria.* Lin. 1112. pte tae Aow, Go Blt. 77. 
J. 1.—D. p. 42=—Lam. 2.—Ch. f. 3, 4.— Mame. t.4.f. 1.—W.t 
2. f. 2.—Don. t.85.—M. Acuraand Mercenartia, Say. Oui: 
thick, rounded at both extremities, but slightly attenuated and pro- 
duced at the anterior end, moderately ventricose, dull whitish or 
pale chesnut under a wrinkled brown or chesnut epidermis ; inside 
glossy white with the syphonal scar larger than in the last ; hinge 

2G. Arctica, Lam. 2, is a Panopea. 
5 See too the Leeviuscula, Plicata, and Vitrea of the same work. 
4M. Ovalis* Turt. Biv. is a young variety of this species. 
¢ 2 
