32 TESTACEOUS MOLLTJSCA. 



Janeiro. — The Oblonga of Say, in Journ. A. N. S. Phil. 2, and the 

 Californica of Conrad, in the seventh vol. of the same work, are (to 

 say the least) closely allied to this species. 1 



M. Pellucida.* Chem.f. 234.— D. p. 144. -M. Depressa. 

 Lam. 29.— M. Dealbata. Mont. p. 95. t. 5./. 1. — IF. t. 6./. 

 32. Sub-ovate, thin, pellucid, white and convex ; disc smooth and 

 depressed, the sides with somewhat plait-like striae. — Brazil. 



M. Lisor. Adanson Senegal, t. 17. f. 16. Ovate-triangular, 

 rather longer and more acuminated anteriorly ; thin, polished, 

 smooth but grooved on the flattened slopes and towards the posterior 

 ventral edge ; umbones rather distant ; lateral teeth, thin, laminar, 

 moderately distant ; either pale fulvous with linear livid rays and 

 the beaks and interior violet, or uniform white, or white with liJac 

 zones and violet beaks, under which is a dark stain internally, 

 f . . 1-L. — Senegal, tfc* 



M. Trigonella. Lam, 31. — E. 259. f. 2? Triangular inequi- 

 lateral white ; hinge with the teeth if any indistinct. — Bay of Sea 

 Dogs. 



M. Truncata. Mont. Sup. p. ^.—Turt.Biv. p. 68. -An. 

 M. Triangularis. Ranieri 1 — M. Subtruncata. Don. t. 

 126. — M. Crassatella. Lam. 33. Triangular, equilateral, 

 solid, convex, anteriorly sub-angulated, depressed from the beaks at 

 both extremities, so that the sides almost form a rectangle at the 

 prominent beaks, ventral edge short and rounded; yellowish white, 

 irregularly striated by the lines of growth ; umbones large and pro- 

 minent; slopes and lateral teeth striated. \^..\\.—N. Europe. 



M. Subtruncata.* Mont. Sup. p. 93. t. 27. f. \.—D.p. 

 \A\.— Turt. B.p. 70.— W. t. 6. /. 23.— Flem. p. 427. Oval- 

 triangular, inequilateral, convex, whitish or yellowish horn colour, 

 with regular coarse transverse striae ; one side truncated, the other 

 produced in a straight line to a rather acute point ; beaks tumid, pro- 

 minent without curvature; lateral teeth striated. f..l. — England. 



M. Australis. Sow. in Beech. Zool. p. 154. an. t. 44. f. 6 ? 

 Subtrigonal, ovate, convex, rounded and rather shorter posteriorly, 

 attenuated and obtusely angulated anteriorly, the ventral edge much 

 arcuated : white under a thin ashy epidermis, polished and nearly 

 smooth : anterior slope obtusely defined, and the edge sloping 

 outwards ; both depressions somewhat grooved : inside pure white, 

 the lateral teeth large, moderately distant and entire. 1^. .1^. — 

 Swan River. 



1 M. Donacia, Lam. 28, belongs to Mesodesma. 



2 This latter variety is probably the Lilacea of Lam. 30. Ovate- 

 triangular, solid, violet-white with violet beaks and zones, smooth, 

 but towards the ventral edge, plicated ; within with a large fulvous 

 spot beneath each beak. 



