162 



a fub-arcuated appearance. Infide white ; margin under 

 the beak quite fmooth. Length rarely exceeds two 

 inches; breadth one inch. 



Da Costa makes no mention of this fpecies. Mr. Pen- 

 nant fpeaks of it from Weymouth, from whence we have 

 been favoured with it by Mr. Bryer. Do61or Piu.teney 

 alfo ftates it to be on the DorfetJJiire coafl ; and exprefTes 

 fome doubt whether it is not the )'oung of the M. Modiolus. 



With refpeft to the fiiape of thefe two (liells, they cer- 

 tainly are extremely fimilar, but in colour they are effen- 

 tially different; befides, the Modiolus is never found beard- 

 ed, is always of a dufi-Ly-black colour, and grows to a 

 very fuperior fize. On the other hand, it muff be admit- 

 ted that young fliells fometimes differ materially in colour; 

 and that, as we never have feen any other which could be 

 confidered as the young of that fiiell, doubts mufl be 

 entertained. 



We have found this fpecies in Cornwall and in Devon- 

 JJiire rarely, and have received it from Sandtcich in Kent ; 

 but it does not appear common any where. 



A variety is faintly radiated. 



The rough, or bearded, appearance of this fliell is oc- 

 cafioned, in part, by the epidermis being broken and di- 

 vided into fibres, which in a foft, and glutinous flate, ar- 

 refts fuch extraneous matter as comes in conta6l. 



Mytilus 



