THE ECONOMIC MOLLUSCA OF ACADIA. 
69 
Island, 1861, mentions Scallops, “ with large ribbed shell, 
and serrated edge,” as occurring on the coast of Prince 
Edward Island. This description would apply both to this 
species and the following, but better to the latter than the 
former.] Probably rather common on Bay of Fundy and 
Atlantic coasts, and much less so in the Gulf of St. Lawrence. 
Habits. This is a more northern species than the last and less 
abundant in our waters. It is much smaller than the latter, rarely 
exceeding four inches in diameter and is readily distinguished from it 
by its raised radiating ribs, fifty to one hundred in number, which bear 
closely crowded, transverse, erect scales. The “ears” or triangular 
projections from the valves which form the hinge, are unequal in size 
and shape in this species, though equal in P. tenuicostatus. In habits it 
appears to resemble the latter very closely, living in perhaps more 
rocky situations, but moving, taking its food and so on, in the same 
way. 
Economics. In its usefulness to man, this species cannot 
be distinguished from Pecten tenuicostatus. It is equally 
good for food and its shells may be used for the same purposes. 
Willis tells us that he has known it to be sold with the latter 
for one shilling sterling, each, in the Halifax market, and 
that it is quite as delicate food. Its greater scarcity must 
make it much less valuable. It is probably never taken 
separately from its larger relative, and is not distinguished 
from it by the fishermen. 
13. Pecten irradians Lamarck. 
Pecten concentricus Say. 
Scallop. 
[ Pecten , a comb; irradians, radiating.] 
Distribution. ( a ) General ; — Low-water mark to thirty 
•or forty fathoms. Gulf of Mexico and Florida, north to 
Massachusetts Bay. Sable Island. 
(b) hi Acadia ; — Reported only from Sable Island, by John 
Willis. 
