APPENDIX. 343 



On Amphidesma (p. 4 1) Reeve has published a monograph of 

 Amphidesma proper, in his ' Conchologia Iconica.' Lamarck (whom 

 we followed in youthful confidence) has evidently, under this appella- 

 tion, confused together several well-defined groups. The A. Boysii, 

 tenue and prismaticum have very properly been separated as Syn- 

 dosmyje ; A. albellum, according to Recluz, is identical with Lutraria 

 Cottardi (p. 28 = A. Sicidum, Sow.) ; the type of A. physoides (p. 43) 

 was a Kellia (I saw it in the French Museum in 1843), but, according 

 to Recluz, it is now destroyed ; of A . nucleoid a Kellia of the section 

 Poronia (teste Recluz an Australian ! species), of A. purpurascens, 

 according to the same author, who has confirmed several of our con- 

 jectures, Ervilia nitens. 



KELLIA, Turton. 



" Somewhat globular, equivalve, closed. Hinge with two approxi- 

 mate teeth and a remote lateral tooth in one valve, and a concave 

 tooth and remote lateral one in the other. Ligament internal" 

 (Turton). 



K. Geoffroyi (as Erycina G. p. 40, t. 12, f. 1) ... K. rubra, p. 43, 

 t. 9, f. 48. Our Mesodesma Cycladea, p. 38, is also a member of 

 this genus, 



ERVILIA, Turton. 



" Oval, equivalve, inequilateral, closed. Hinge with a single erect 

 tooth closing between two small divergent ones in the opposite valve ; 

 lateral teeth none. Ligament none." 



E. nitens, p. 43, t. 9, f. 6. The Donax castanea of the earlier 

 British writers (Turk Dith. t. 10, f. 13, as Capsa c.) is, also, a 

 member of this genus. 



Cumingia coarctata (t. 12, f. 37), Sow. Z. P. 1833, p. 34: G.— 

 Reeve, C. S. t. 49, /. 4. Resembling C. Tellinoides, but not so cunei- 

 form in front, with the laminar wrinkles further apart and usually 

 more elevated, and their intervals with scarcely perceptible radiating 

 striulae. ^q. Mexico. Seems a variety of C. lamellosa. 



Cumingia Tellinoides (t. 12, f. 38). — Mactra T. Conr. J. 

 Philad. 6, p. 258 ; Am. Mar. C. t. 14, /. 2.— C. T. Gould, Mas. 

 p. 5.0, /. 36. Oval-cuneiform, equilateral or nearly so, fragile, com- 

 pressed and wedge-shaped in front, semi-oval and decidedly convex 

 behind, dull uniform white, with close concentric laminar wrinkles, 

 whose intervals are unsculptured ; ventral edge incurved in front, 

 subarcuated behind ; dorsal areas impressed. -J^.,..-^. N.America. 



