512 mytilinjE. 



Genus mytilus, Linnaeus. 



Mantle freely open ; ventral margin simple ; branchial 

 furnished "with pinnated fringes ; anal opening plain and 

 sessile. 



Shell equivalve, very inequilateral, sub-triangular, more 

 or less tumid, rounded behind ; surface of valves covered 

 with an epidermis ; beaks almost straight, terminal, pointed. 

 Hinge without teeth ; ligament linear, marginal, sub- 

 internal. Muscular impressions two, unequal ; pallial im- 

 pression obscure, simple. Byssus strong and coarse. 



Sy?i. Mytulus. Musculus, Rondelet. Callitriche, 

 Callitrichoderma, Poll. Perna, Schwn., Retz., not Adans. 

 Chloromya, Mbrch. 



Ex. M. edulis, Linnaeus, pi. 121, fig. 1. Shell, M. 

 edulis, fig. 1, a, 1, b. 



The genus Mytilus includes many species, which are 

 world-wide in their distribution, being found in Behring's 

 Straits and the Black Sea, at Cape Horn, the Cape 

 of Good Hope, and New Zealand. They are usually 

 found attached by a byssus either to stones or floating 

 bodies. The ligulate, grooved foot has the power of 

 spinning the silky material of the byssus when the 

 animal requires temporarily to anchor itself. They produce 

 small and inferior pearls, and the animals are used as bait 

 in deep-sea fisheries. 



Species of Mytilus. 



achatinus, Lam. albus, Siem. 



Africanus, Chem. angustanus, Lam. 



