38 TESTACEOUS MOLLUSCA. 
§ Ic. f- 12, Arcuated, the anterior extremity carinated and form- 
ing a sharp beak, concentrically grooved, whitish rayed with inter- 
rupted chesnut spots: chesnut within. }..1.—New Holland and 
Singapore.! 

1 Glabrata Lam. 5, Cuneata 8, Erycinea 9, Cycladea 10, and Striata 
11, belong to MesopEsma, which Deshayes thus characterises. 
MESODESMA. 
Oval, transverse or triangular, and usually shutting close: hinge 
witha narrow central spoon-shaped pit for the ligament, and on 
each side of it an oblong and simple tooth. 
M. Donacta. Desh.—Mactra D. Lam. 28.—E. vol. 3. p. 442. 
Reeve. t. 45. f. 4. Solid, transverse, striated ; posterior side very 
short and subtruncated, anterior very produced. 2.— Peru. 
M. Guasrata. Desh.—An. Mactra G. Gmel. 3258.—E. t. 
257. f. 8.— CRASSATELLAG. Lam. 5.—An. Macrra TAPROBANEN- 
sis, W. S. ¢t. 1. f. 12. Triangular, solid, white, grooved at the 
ventral edge and anteriorly, the beaks and umbones glabrous. 1.— 
Ceylon. 
M. Compranata. Erycina C. Sow. G. f. 6.—M. Graprara. 
Reeve, t. 45. f. 6. Ovate-subtriangular, rounded at both ends, 
inequilateral, rather compressed, solid, white under a perfect gla- 
brous olive green cuticle; ventral edge rather arcuated. +..1 iiss 
tralia. Erroneously quoted by by Deshayes as a synonym. of Cr. 
Glabrata Lam. 
M. Cuneata. Desh.—Crassatetta C. Lam. 8.—M. Sustri- 
ANGULATA. Gray. in Grif. Cuv.—W. S. f. 10. (fide Gray in 
B. M.) Solid, transverse, smooth, somewhat wedge-shaped : pos- 
terior side very short subtruncated, whitish. 1.—New Holland. 
Shape of a Donax. 
M. Cycuapra. Desh.—Crassatetta C. Lam. 9. Obtusely 
triangular, thin, gibbous, reddish grey, finely striated transversely : 
erica Bonita ate pearly, lateral teeth rather long.—/S. America. 
Shape and size of Cyclas Cornea. 
M. Erycina. Desh.—CrassaTevia E. Lam. 10.—Del. t. 4. 
J. 4.—Ast. t. 82. f. 1, 2, 3,4. Triangular, smooth, greenish-ful- 
vous, rather depressed : beaks decorticated.—Van Diemen’s Land. 
pe Srriata. Desh.—Crassatetyta 8. Lam. 11.—Macrra 
. Gmel. 3257.—W. t. 6. f. 16.—D. p. 137.— Ch. f. 222, 3-— 
eal S. Son. G. f. 2.—F. t. 254. f. 4. Triangular, com- 
pressed, whitish, with numerous thick transverse sroovelike striae ; 
beaks glabrous. 1.—New Holland. 
M. Cuemnirai. Desh.—Reeve. t. 45. f. 1.—Mya AUSTRALIS. 
Gel. 3321.—Mactra A. D. p. 141 ==Ch. fi 19, 20.— Ast. t. 82. 
