THE ECONOMIC MOLLUSCA OF ACADIA. 
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15. Modiola modiolus (Lin.) Turton. 
Nytilus modiolus , Lin. 
Horse-Mussel. 
Modiola, a little measured); modiolus , a little measure(’). 
Distribution, (a) General; — Low- water mark to one 
hundred fathoms. New Jersey to Arctic Ocean, and circum- 
polar. On European coast, southward to France; on Asiatic, 
to northern Japan; on western American, to California. 
(b) In Acadia ; — (in N. B.) Abundant on the southern 
■coast everywhere from Grand Manan at least to St. John. 
Shediac, Wliiteaves. (In N. S.) Annapolis Basin, somewhat 
abundant, Verlcruzen. All rocky shores, Jimes. (InP.E.I.) 
Not reported but doubtless occurs. Probably to be found in 
rocky situations around the entire coast. 
Habits. This species more closely resembles Mytilus edulis than any 
•other Mollusc. It is generally larger than the latter, growing to a 
length of six, and in extreme cases, mentioned by Willis, eight inches. 
FlG. 12. — Modiola modiolus. Natural size. 
It never has the blue black color of M. edulis, but instead has an 
epidermis of a dark chestnut or brown color. The umbo (or centre 
around which the lines of growth of the shell are arranged) is at the 
anterior or small extremity in M. edulis, but set a little back on the 
hinge margin in this species. 
It does not, however, live in great beds above low-water mark as 
does M. edulis. It prefers gravelly and stony bottoms to which, half 
buried in the former, and half hidden in crevices in the latter, it 
