RELATIVES

We already noted that three kinds of blue mussels are  closely related.  They are often hard to tell apart.

The California mussel,  Mytilus californianus, is a more distant relative.  It is restricted to the wave exposed coast where it thrives,  reaching a size of up to 30 cm in length.

Mussels belong to the class Bivalvia which includes clams, scallops, cockles, rock jingles and even shipworms--which, incidentally, aren't worms at all.

Swimming scallop

California mussel

 

Photos by Bill Austin,

Marine Ecology Centre