38 TESTACEOUS MOLLUSCA. 



fy Ic.f. 12. Arcuated, the anterior extremity carinated and form- 

 ing a sharp heak, concentrically grooved, whitish rayed with inter- 

 rupted chesnut spots : chesnut within, f . . 1. — New Holland and 

 Singapore. 1 



1 Glabrata Lam. 5, Cuneata 8 , Erycinea 9, Cycladea 10, and Striata 

 11, belong to Mesodesma, which Deshayes thus characterises. 



MESODESMA. 



Oval, transverse or triangular, and usually shutting close : hinge 

 with a narrow central spoon-shaped pit for the ligament, and on 

 each side of it an oblong and simple tooth. 



M. Donacia. 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. Glabrata. Desh.— An. Mactra G Gmel. 3258.— E. t. 

 257. f 8. — CrassatellaG. Lam. 5. — An. Mactra 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. Complanata. Erycina C. Sow. G.f 6. — M. Glabrata. 

 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^ — Aus- 

 tralia. Erroneously quoted by Deshayes as a synonym of Cr. 

 Glabrata Lam. 



M. Cuneata. Desh. — Crassatella C. Lam. 8. — M. Subtri- 

 angulata. Gray, in Grifi 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. Cycladea. Desh.— Crassatella C. Lam. 9. Obtusely 

 triangular, thin, gibbous, reddish grey, finely striated transversely : 

 within somewhat pearly, lateral teeth rather long. — S. America. 

 Shape and size of Cyclas Cornea. 



M. Erycina. Desh. — Crassatella E. Lam. 10. — Del. t. 4. 

 /. 4. — Ast. t. 82. f. 1, 2, 3, 4. Triangular, smooth, greenish-ful- 

 vous, rather depressed : beaks decorticated. — Van Diemen' s Land. 



M. Striata. Desh. — Crassatella S. Lam. 11. — Mactra 

 S. Gmel. 3257.— W. t. 6.f 16.— D. p. \37.— Ch.f. 222, 3.— 

 Erycina S. Sow. G. f 2. — E. t. 254. f. 4. Triangular, com- 

 pressed, whitish, with numerous thick transverse groovelike striae; 

 beaks glabrous. 1. — New Holland. 



M. Chemnitzii. Desh. — Reeve, t. 45. /*. 1. — Mya Australis. 

 Gmel. 3321.- Mactra A. D. p. 141.— Ch.f. 19, 20.— Ast. t. 82. 



