45 



This fpecies, firft defcribed by Doctor Maton and Mr. 

 Rackett, in the work referred to, was difcovered by Mr. 

 M'^Leay, on the coafl of Caithnefs. A fpecimen which we re- 

 ceived from Scotland, is covered with a pale yellowifh-browai 

 epidermis in the fiilci, but worn off from the elevated parts, 

 fhewing the fliell to be white. In this fpecimen not Icfs 

 than twenty-two fuici can be coimted. 



Very fmall fpecimens, not exceeding a quarter of an inch 



diameter, and of a pure white, we have feen from the Frith 

 o{ Forth. 



Shell thick, tranfverfely ovate, fub-comprelTed, and fur- Danmonia. 

 nifhed with many regular, equidiftant, ftrong, concentric Tab. 29. f. 4. 

 ridges, which, with the intermediate /J^/c/, are quite fmooth, 

 but covered with a dark rui'ous-hrown epidermis, beneath 

 which the fhell is white : the lanbo is nearly central, and 

 fomewhat reclined : the cartilage Hope linear : cordiform 

 depreflion lanceolate. Infide white, but not gloffy, except 

 round the margin, which is alfo finely crenated : the hinge 

 is furniflied with twa flrong primary teeth in each valve. 

 Length an inch ; breadth an inch and a quarter. 



A live fpecimen of this new and interelling fpecies was 

 taken by the trawl, in deep water, off the coafl of Devon, 

 and brought to us with the animal in it. 



In many refpecls it is fo nearly allied to Fe?ius Scotica, that 

 at firft fight one might be naturally led to coniider it the 



fame. 



