38 TESTACEOUS MOLLUSCA. 



8f 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, f . . 1 . — New Holland and 

 Singapore.^ 



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 usiiaUy shutting close : hinge 

 with a narrow central sjjoon-shaped pit for the ligament, a7id on 

 each side of it an oblong and simple tooth. 



M. Donacia. i^e-s/i. — MactraD. 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. Desk.— An. Mactra G Gmel. 32oS.—E. f. 

 257./. 8. — CrassatellaG. Lam. 5. — ^?/. Mactra Taprobanen- 

 sis, W. S. t. \. f. 12. Triangular, solid, white, giooved 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, f. . 1^ — Aus- 

 tral/a. Erroneously quoted by Deshayes as a synonym of Cr. 

 Glabrata Lam. 



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

 angulata. Gray, in Grif. Cuv ~W. S.f. 10 {fde 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. Des/t.— Crassatella C. Larn. 9. Obtusely 

 triangular, thin, gibbous, reddish grey, finely striated transvei'sely : 

 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. Lain. 11. — Mactra 

 S. Gmel. 3257.~W. t. 6./. 16.— Z>. p. \31.-Ch.f. 222, 3.— 

 Erycina S. Sow. G. f. 2. — E. t. 2o4. f. 4. Triangular, com- 

 pressed, whitish, with numerous thick transverse groovelike striae; 

 beaks glabrous. 1. — New Holland. 



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

 Gmel. 3321.- Mactra A. D. p. \4\.— Ch.f 19, 20.— Ast. t. 82. 



