58 LUCINID.Ti. 



Lttcina lactea. Lam. (not Philippi), Anim. s. Vert. (ed. Desh.) vol. vi. p. 229 



(chiefly), — TuRT. Dithyra Brit. p. 112, pi. 7, f. 4, 5. — Brit. 



Marine Conch, p. 71. — Brown, Illust. Conch. G. B. p- 98, 



pi. 39, f. 3.— Hanl. Recent Shells, vol. i. p. 76. 



„ Amphidcsmoides, Desh. Encyclop. Methodique, Vers. vol. ii. p. 375. 



Ampliidesma Lucinalis, Lam. Anim. s. Vert. (ed. Desh.) vol. vi. p. 1 27 (fide 



Philippi). 

 Lucina leiicoma, Turt. Dithyra Brit. p. 113, pi. 7, f. 8. — Brit. Marine Conch. 



p. 72. 

 Lorijies lactea, Flem. Brit. Anim. p. 430. — Macgill. Moll. Aberd. p. 256 ? — 

 Brown, Illust, Conch. G. B. p. 98, pi. 39, f. 29. — Blainv. 

 Manuel Malacolog. pi. 72, f. 1. 



The shape of this shell is very nearly orbicular, and the 

 valves rather strong, opaque, almost entirely devoid of 

 lustre, and of an uniform white both within and without. 

 They are almost equilateral, convex, and usually more or 

 less ventricose at the umbonal region, where the chief swell 

 exists, diminishing gradually and tolerably evenly from 

 thence towards the margins. The surface, which appears 

 peculiarly liable to indentations, is not striated, nor yet 

 quite smooth, but is concentrically traversed by antiquated 

 lines of growth. The upper front corner of the adult is pe- 

 culiarly compressed, as an extremely indistinct very shal- 

 low and rather broad sulcus, emanating from the beaks, 

 runs close to the dorsal edge, and slightly indents the upper 

 part of the front margin at its extremity. The ventral or 

 lower outline is moderately arcuated, and rises rather the 

 more in fi-ont, which occasionally (for it varies in extent) 

 gives an air of obliquity to the contour ; it is not flattened 

 on either side, though it is usually rather the more curved 

 behind. The anterior side is rather the shorter, and de- 

 cidedly the narrower. Both dorsal edges decline in but a 

 very trifling degree ; the hinder, which is rather the higher, 

 is almost straight, or but slightly convex, the front one, 

 which is rather the more sloping, after passing the lunule, 

 becomes a little convex likewise. Both extremities are 



