1) Genus mytilus 2) Mollusk genus 
[genus] Mytilus is a cosmopolitan genus of medium to large-sized edible saltwater mussels, marine bivalve molluscs in the family Mytilidae. Species within the genus Mytilus include: ==Human use== Mytilus mussels are widely exploited as food and used in mariculture. For instance, in California, they have been consumed by coastal Native Ameri...
• (n.) A genus of marine bivalve shells, including the common mussel. See Illust. under Byssus.
Myt'i·lus noun [ Latin , a sea mussel, Greek ....] (Zoology) A genus of marine bivalve shells, including the common mussel. See Illust. under Byssus . 
[n] - type genus of the family Mytilidae: smooth-shelled marine mussels
genus Mytilus noun type genus of the family Mytilidae: smooth-shelled marine mussels