Blainville only as subgenera of Mytillus ; and however 

 closely allied we may acknow^ledge them to be, those gen- 

 era may be distinguished by having the posterior margin 

 arquated somewhat prominently, the apices or beaks not 

 being terminal as in Mytillus. The latter naturalist gives 

 the following account of the animal. "Body oval, dila- 

 ted ; mantle open at its inferior middle only, which at its 

 anterior extremity is fringed ; foot linguiform, canalicu- 

 late, with a byssus at its base and many pairs of retractor 

 muscles ; mouth with simple lips ; two adductor muscles, 

 of which the posterior one is very small. 



Several species are eatable, and the common Muscle of 

 Europe (M. edulis, L.) is taken to market in large quanti- 

 ties for the table. All the species are marine with the ex- 

 ception of the M. polymorphus, Gm. or Chemnitzii 

 which inhabits the Danube and the Commercial Docks 

 near London, but which is probably not strictly speak- 

 ing of this genus, if we may judge b}^ the somewhat cham- 

 bered appearance of the beak cavity. 



They attach themselves by means of their byssus to 

 rocks, stones and other tixed bodies and even to one anoth- 

 er. The species are numerous ; Lamarck enumerates 

 thirty seven, of which two are fossil, and several have been 

 more recently described. Some species are infested by a 

 parasitical Pinnotheres. 



