208 PANDORID^. 



Pandora rosirata. Lam. Anim. s. Vert. (ed. Desh.) vol. vi.p. 145. — Brit. Marine 

 Conch, p. 58. — Brown, Illust. Conch. Ci. B. p. 104, pi. 47, 

 f. 5, 12, 13.— SowERBY, Gen. Shells, Pandora, f. 1, 2, 3.— 

 Crouch, Introd. Conch, pi. 5, f. 2. — Sowerby, Spec. 

 Conchylior. Pandora, p. 2, f. 7, 8, 9. — Sowerby, Conch. 

 Manual, f. 90.— Desh. Elem. Conch, pi. 8, f. 10, 11.— 

 Reeve, Conch. Systemat. pi. 37, f. 1, 2, 3. — Hanl. Re- 

 cent Shells, p. 48. — Desh. Exp. Scient. Alg^rie, Moll. pi. 

 24 (animal). 



„ margaritacea, Turt. Dithyra Brit. p. 40, pi. 3, f. 11 to 14. 



„ incequivalvis, Flem. Brit. Anim. p. 466 (chiefly)- 

 Pandore rostrte, Chenu, Traite Element, p. 58, f. 194, 195. 



This peculiarly graceful bivalve, which we may reckon 

 among the rarer shells of the British Fauna, is of an 

 elongated oblong shape, extremely inequivalve, and for its 

 genus sufficiently strong. It is semitransparent, and coated 

 with a thin layer of yellowish white ; beneath which it is 

 pearly ; and, indeed, the nacreous lustre is more or less 

 visible, especially in the young, upon the outer surface also. 

 The valves are remarkably unequal ; the left one being 

 greatly convex, and smooth, with the exception of some 

 irregular concentric striulaj towards the side ; the right 

 being almost flat throughout (a little concave in the young, 

 and towards the beaks), with similar most closely-disposed 

 irregular minute striula? at the sides, and especially in front, 

 besides obsoletely indented folds toward the upper portion 

 of the area. The ventral margin is not (for a Pandora) 

 greatly arcuated, being even in certain examples a little 

 flattened in the middle of the arch ; its chief swell is in 

 front, becoming less convex, but gradually and most dis- 

 tinctly ascending, posteriorly. A perpendicular let fall from 

 the beaks (which, although by no means prominent, are, 

 nevertheless, through the inflection of the hinder dorsal 

 margin, more manifest than in the succeeding species,) 

 would about equal a similar one dropped from any other 

 portion of the upper edge, and would sever an anterior 



