Bull. U. S. B. F., 1921-22. (Doc. 922.) 



Fig. 100 —The sea mussel Mytilus edulis Linnaeus, showing foot distended and attachment by byssus. 



Fig. ioi.— A bed of sea mussels in Menemsha Pond, Marthas Vineyard, Mass., exposed at low tide, 

 of surface is covered with more than a bushel of the shellfish. 



Each square yard 



