344 DONACID^. 



the (lays of Montagu to the most recent period, and not 

 merely cast upon the shores, but by dredging (S. H. 1848) 

 in deep water in fifty-four fathoms between Scilly and Corn- 

 wall (M 'Andrew) ; and in twenty fathoms near Penzance 

 (M' Andrew and E. F.). In a recent state these valves are 

 partially covered by a slight yellowish epidermis, of a some- 

 what horny texture. 



SPURIOUS. 

 E. NiTExs, Montagu. 



Mya nilcns, Mont. Test. Brit. Suppl. p. 1G5. — Turt. Conch. Diction, p. 103. — 

 Laskey, in Werner. Memoirs, vol. i. pi. 8, f. 4. — Wood, Gene- 

 ral Conch, p. 101. — DiLLw. Recent Shells, vol. i. p. 47. 

 Ampliidesma jmrpiirascens, Lam. Anim. s. Vert. (ed. Desh.) vol. vi. p. 129. — 



Hanl. Recent Shells, vol. i. p. 43. 

 Ervilia nitens, Turt. Dithj-ra Brit. p. 5G, pi. 19, f. 4. — Flem. Brit. Anim. p. 431. 

 — Brit. Marine Conch, p. 5. — Sowerb. Conch. Manual, f. 497. 

 — Hanl. Recent Shells, p. 43. — Recluz, Mag. de Zool. 1845, 

 Moll. pi. 96. — Recluz, in Chenu, 111. Conch. Ervilia, p. 3. — 

 Philippi, Wiegman's Archiv. f. Naturg. 1847, pi. 3, f. 9. 

 Syndosmya purpiirascens, Recluz, Rev. Cuvier. Zool. 1843, p. 365. 



The contour is oval and very slightly oblique, and the valves 

 glossy, tolerably strong, compressed, and regularly and closely 

 sculptured with concentric stria), which usually cover the entire 

 surface ; we possess, however, a young variety difFeriug in no 

 other respect, in which they are entirely obsolete on the longer 

 side. The colouring (which is both externally and internally the 

 same), varies from uniform rose colour to almost pure white, but 

 is usually of a darker or lighter tint of the former, becoming pale 

 or colourless towards the ventral margin and at the shorter side. 

 The valves are devoid of any umbonal ridge, and rounded at both 

 extremities, the front tapering in some degree, and the hinder 

 termination being considerably attenuated. The ventral edge 

 (which is entire within), is considerably, yet not regularly, ar- 

 cuated, ascending chiefly in front j the dorsal margin slopes deci- 

 dedly on either side, but more so in front, where it is nearly 

 rectilinear, than behind, where, as it recedes from the middle of 



