DONAX. 339 



sible, when the tliflerences between this and the trunculus 

 of the British conchologists are clearly understood, the 

 discrimination of other individuals may establish a claim 

 for this shell to be regarded as indigenous. At present 

 the sole specimen we have seen, now in the collection 

 of Mr. Metcalfe, was taken (not living) by Dr. Battersby, 

 at Torquay. As that gentleman has no foreign collec- 

 tion, and is of the most unimpeachable veracity, no doubts 

 could rest upon its British origin, were it not that Torquay 

 has for years been so closely investigated, as to render 

 it extremely improbable, supposing the species to be truly 

 native, that other examples should not exist in some of the 

 numerous collections continually being formed at that at- 

 tractive watering place. 



Hence, from what may not unlikely be esteemed an over- 

 cautiousness, we prefer at present regarding it among our 

 doubtful species ; indeed, its mention at all, contrary to 

 our usual rule of confining our attention in the supposed 

 spuriously indigenous, to those mentioned in print (for 

 otherwise the number of the excluded would far exceed 

 those of undoubted British origin), is solely owing to the 

 highly respectable authority of the naturalist we have 

 mentioned. 



The valves are oblong wedge-shaped, very inequilateral, 

 strong, and not very convex. They are covered with a 

 very thin epidermis, of darker or lighter shades of fulvous 

 or buff-coloured yellow, beneath which the surface is usu- 

 ally of a glossy liver-colour, with often linear paler rays, 

 but sometimes even of a pure uniform white. The ventral 

 margin slightly bulges out anteriorly, and greatly ascends 

 at that extremity which is obtusely rounded, and not 

 much attenuated. The hinder side is scarcely equal to 

 one fourth of the front ; its blunted wedge-shaped termi- 

 nation is very abrupt, as the hinder dorsal edge slopes 

 most suddenly and deeply from the ligament ; the front 

 dorsal edge is tolerably straight and but slightly declining. 

 The beaks are somewlmt inchned, and not acute ; the 

 lunule is linear and deeply excavated, and the posterior 



