24 



the fmaller end. Infide fmootli and glofly ; hinge fumiflied 

 with a horizontal tooth, having a fub-triangular depreihon 

 for the reception of the conne6ling cartilage, and a minute 

 eretl tooth in both valves, befides a fmall lamina or lateral 

 tooth in one valve on each fide, remote ; of which the other 

 is deftitute. Length three-eighths of an inch; breadth 

 double its length. 



This nondefcript fpecies of Mactra was firft noticed in the 

 year 1803, by Mr. Laskey, on Beltnn fands, near Dutibar, 

 in Scotland; and fince by the fame gentleman, together with 

 Mr. H. Boys, on the fands between Porto Bello and Muffl'l- 

 hurgh, where they are fometimes, after a turbulent fea, 

 tolerably plentiful. 



Thefe gentlemen, to whom we are under obligations for 

 fpecimens, had given it the trivial name prefixed, from the 

 circumftance of its refle^ing in fome particular lights, 

 ftrong prifmatic colours, and which will in part be a diftin- 

 guilhing chara6ler : this refplendent hue, however, is not 

 peculiar to this fliell» as Tellina fubiila, which is fomewhat 

 fimilar in Ihape, poffefles that iridefcent glois in a confider- 

 able degree. 



A fmgle valve of this fpecies having occurred on the 

 coafl of Devon, is fufficient to identify it as a produdlion alfo 

 of South Britain. 



Shell 



