DOx\AX. 409 



and smooth, olivaceous : margins gently curved in front, with- 

 out any indentation or sinuosity, obliquely and gradually trun- 

 cate on the posterior side, which ends in a blunt and rounded 

 point and has a slightly angular slope ; anterior margin semi- 

 oval and wedge-shaped ; dorsal margin on that side long and 

 nearly straight, and on the posterior side about two-thirds as 

 long and equally straight, the point of their divergence repre- 

 senting an angle of about 70 degrees : beaks small, pointed, in- 

 curved, and turned towards the posterior side : ligament very 

 short, partly prominent, the lower half being imbedded in the 

 hinge-plate, horncolour : corselet long, rather deep, with thick- 

 ened and somewhat projecting edges : hinge-line set at a very 

 obtuse angle : lunge- plate thick, much longer but narrower 

 on the anterior than on the posterior side, abruptly truncate at 

 the end of the ligament, in consequence of the latter being 

 partly imbedded in it : teeth, cardinals as in D. vittatus, but 

 much slighter and ordinarily not so distinctly cloven ; laterals 

 as in that species, developed in the young but nearly oblite- 

 rated in aged individuals : inside highly polished and glossy, 

 tinged with violet, or else milk-white with a ilamecolour stain 

 on the anterior dorsal side, besides a dusky-purple streak near 

 the beak on that side and two others of the same hue on the 

 posterior side ; margin closely and minutely crenulated in every 

 part except the hinge-line : paJlial scar slight, with a tongue- 

 shaped sinus extending from the posterior side about halfway 

 across the interior of the shell : muscular scars distinct, ante- 

 rior triangularly oblong and irregular, posterior smaller and 

 nearly circular. L. 0*7. B. 1*35. 



Habitat : In sand, at the low-water mark of spring- 

 tides, and at the depth of a few fathoms, in the Channel 

 Isles and on some parts of the Devonian and Cornish 

 coasts ; frequently in Ban try Bay among the " Coral- 

 sand " procured for manure, and which is so productive 

 of good shells. Leach states that it is common on most 

 of our shores, and specifies South Wales as one of the 

 localities ; but, although that was for the greater part of 

 my life my home and chief " hunting-ground," I never 

 found this species in the Principality nor learnt from 

 any of my correspondents that it had been discovered 

 there : D. vittatus must have been mistaken for it. The 



