179 



P. with a pellucid, thin, brittle (liell, of a light horn- 

 colour, darker towards the beak, where it is faintly varied 

 with purple and blueifli-green; it is marked with about 

 eleven longitudinal (tria:, or rather ribs, the whole length 

 from the apex to the oppofite margin, furnilhed with con- 

 cave fpines, encreafing in fize at the larger end; about 

 one third of the (hell, on the fide oppofite the hinge, is 

 deftitute of ribs ; and is finely ftriated obliquely to the ribs, 

 on which the fpines are very fmali, and the concave fides 

 turn outwards; the hinge fide is nearly ftrait, turning a 

 little towards the beak: the other fide bends a little in- 

 ward under the beak, and is fomewhat convex in the mid- 

 dle. Breadth three inches at the gaping end, which is 

 fomewhat rounded ; length fix inches and a half, taper- 

 ing to the apex; the hinge fide rather the longefl. In- 

 fide fmooth, with a pearly hue : beneath the apex feveral 

 tranfverfe, cartilaginous lamina?. 



A fhell of the above fize we received from a friend, who 

 took it in trawling off the Edijlone near Plymouth: It is 

 fometimes taken by the fifhermen about Torhay and on 

 the DorfetJIiire coafl:; and we have feen it from the coafl 

 of Sujfex ; but mofl times of a fmall fize, not exceeding 

 three or four inches in length. 



Da Costa was certainly miftaken, in making this the 

 P. imiricata of LinnvEUS; that has been found in En- 

 gland rarely, according to the Catalogue of Dorfet iliells 

 by Doftor Pulteney, and is perfeftly diflinft. 



A a 2 Pinna 



