TRIBE MACTRACEA. 31 



M. SuBPLiCATA. Lam.. 1/. — Cli.f. 205, 6. Triangular, thin 

 white, somewhat plaited at the sides near the beaks, disc smooth ; 

 hinge with a lateral bilobed tooth. — A large species intermediate 

 betrveen Carinata and Striaiella, having its anterior slope on each 

 side bounded by an angle as in. Plicataria. 



M. Triangularis. Lam. 19,.— E. t. 253. /. 3. Triangular, 

 solid, white with transverse plaits and scattered chesnut spots which 

 become larger as they approach the margin ; slopes grooved ; lateral 

 teeth cross-ribbed and elongated. — Tite figure quoted by Laniarc 

 is nearly twice as broad as it is long, depressed and marked with 

 darker transverse bands on the depressions. A.. 14-. 



M. Lactea. La77i. 19. — An. Gmel. no. 11? — M. Solida. 

 Payr. p. 30. — Poli. 1. t. 18./. 13,4. (magnified).— A^.M.Corai.- 

 LiNA. Lin. ? Ovate-triangular, sub-equilateral, rather longer and 

 slightly narrower posteriorly, very white, sub-turgid, thin, pellucid, 

 delicately striated concentrically, the ventral edge much rounded, 

 f . — Mediterranean. Poli represents tlie depressions as very strong 

 and apparently grooved. 



M. Abbreviata. Lam. 20. Obtusely triangular, transversely 

 shortened, white with the depressions elegantly plaited. If. — Port 

 Jackson in New Holland. 



M. OvALiNA. Lain. 21. — Deless. t. 3. f. 7. Ovate, thin, pel- 

 lucid, white, finely striated near the margin, anterior slope bounded 

 by an angle; beaks very smooth. 1#. — Indian Ocean? 



M. Alba. Lam. 22. — Ch. f.'' 220, I'i-E. t. 254./. 5? 

 Obtusely triangular, turgid, diaphanous ; with minute transverse 

 strise, and a few longitudinal obsolete lines. 2. — Indian Ocean. 



M. Solida. Lin. 112G.— i>. p. MO.— Lam. 23.— Don. t. 61. 

 —Ch. f. 229, O.—Mont. p. 92.— Turt. B. p. 67.— TF. t. 6./. 

 21. — List. t. 253. f. 87. Sub-triangular, nearly equilateral, thick, 

 opaque, shghtly depressed from the beaks at both extremities, nearly 

 smooth, with a few coarse concentric ridges, yellowish-white ; within 

 glossy white and the lateral teeth striated. Ij . . If. — Europe.^ 



M. Squalida. Lam. 26. Sub-triangular, tumid, insequilateral, 

 yellowish obscurely speckled with fulvous ; anterior side the longer, 

 and stained with brown. 1^^^. — The shell I have figured agrees 

 exactly with this brief description, but is, I fiear, no moj'e than a 

 variety of Macidata. 



M. Brasiliana. Lam. 27. — An. M. Fragilis, Ch. f. 235.— 

 An. D. p. 145. in part. — Turt. B. t. 4. /. 10. Ovate-elliptical, 

 sub -equilateral, sub-triangular, nearly smooth ; anterior slope with 

 obhquely diverging longitudinal striae, epidermis brown. 2f . — Rio 



^ M. Castanea, Lam. 23, is a depressed and rubbed variety of this 

 species, and M. Rufa, Lam. 24, is a rubbed Stultorum. 



