30 



For the knowledge of this nondefcrlpt fi^ecies we are in- 

 debted to Mrs, Bryer, reli(5l of our late valuable friend, who 

 lias fo largely contributed towards the former part of tliis 

 work, TJiis lady has continued that liberality which fo 

 confpicuoufly marked the fcientific refearches of our much 

 lamented friend, by prefenting us with his cabinet, which 

 confifls of moll of the f])ecies of fhells belonging to the coafl 

 about JVcymouth, amongft which we had the pleafure to ob- 

 ferve this marked as indigenous. 



It is quite Imix^fTible for the conchologift to compare this 

 with M.JluItorum without inftantly perceiving the diftin(5lion ; 

 in faffc the fame difference fubfifts between them, as between 

 Maclra tnmcata and folida with refpe(51: to the depth of the 

 fliell, prominency of the umho, and flattened or truncated 

 fides. The valves of M. cinerea are more concave than M. 

 Jltdtorttm, more angulated, and rather broader in proportion 

 to their length. It is poflible thefe two fhells may have been 

 liitherto confounded, but it muft be confefl'ed this has never 

 before come under our examination, although we have 

 obtained M. flultomm from various and diflant parts of the 

 kingdom. 



The few fpecimens of M. cinerea in our pofTeffion are 

 nearly deltitute of markings, there being only one or two 

 obfolete pale rays, and the margin only covered with an 

 epideimis, which is brown, inclining to ferruginous at one 

 end, 



]\Iactra 



