170 NEW-YORK FAUNA — MOLLUSCA. 
3. O. canadensis. Shell elongated, subcurved, broad above, very thick and lamellar; upper 
valve convex. Although closely allied to the preceding, it appears to be constantly 
distinct. It is larger, wider, of excessive thickness, and its lower beak does not ap- 
pear to be so much elongated. Length, about eight inches. Sea of Canada, at the 
mouth of the Gulf of St. Lawrence ; and also near New-York. 
Dr. Gould attributes to the virginica (or, as he calls it, virginiana, after Lister) the addi- 
tional character of the ligamentary eminence of the upper valve, extending back to the apex;- 
and thinks that canadensis may be a variety of this, or of borealis. 
This, according to Dr. Gould, is the common oyster of the Chesapeake, and also found 
on the coast of Massachusetts and at the mouth of the St. Lawrence. ‘The dealers in oysters 
know of only two principal varieties, the northern and southern; or as they distinguish them, 
the Chesapeake and York-bay. ‘They distinguish the latter (borealis) by its broader and less 
ponderous and massy shell; its lips are more frequently upturned, and always thinner and 
more brittle. They pretend to be able also to distinguish them by the smell alone ; the shell 
of the northern oyster having quite a strong smell, savoring of the odor of the marine plants. 
The period of longevity in the oyster is not ascertained, but most dealers agree that it is 
in its best condition from the fourth to the sixth year. It rarely lives beyond its twelfth or 
fifteenth year, although they think it probable that a few pass that period. At the end of 
six months the young oyster is found attached to stones along the shore, of a reddish tint, 
with radiating strie, and about the size of a quarter of a dollar; and at the end of the year, 
as large as a dollar, although this increase depends upon locality. A smooth gravelly bottom, 
with about a quarter of an inch depth of fine ooze, is generally preferred: if the deposit is 
deeper, they become excessively elongated and slender, with the margins of the valves drawn out 
into thin plates, and the oyster has a disagreeable muddy flavor. With age, the strong folds 
disappear, and by the fifth or sixth year are only seen on the margin; at a later period they 
are almost entirely effaced, and the species cannot be distinguished from the virginica, more 
especially when these latter have been planted for some time in the New-York waters. 
The oyster appears to thrive best, and attain its most luscious flavor on our coast, between 
the thirty-sixth and forty-second parallels of latitude ; and is supposed, by those who have 
had opportunities of comparison, to be the best in the world. ‘The consumption is almost 
incredible. Independent of those actually consumed, thousands of tons of the young are 
annually exported to the eastern ports for the purpose of planting, and an equal uumber 
introduced from the Chesapeake for the same purpose. 
Beside man, the oyster has many enemies ; and were it not for their wonderful fecundity, 
they would, ere this, have been extirpated. They are taken with oyster rakes or tongs; and 
where the water is too deep for these instruments, a strong iron dredge or drag is employed. 
The Star-fish (Uraster rubens, Forbes) is frequently found clasping the valves of the oyster 
in such a manner as to prevent their opening, and, as the oystermen assert, the oyster perishes 
from suffocation, the valves open, and he is devoured by the starfish. Numerous minute 
