THE ECONOMIC MOLLUSCA OF ACADIA. 
103 
Works of Reference. 
The Oyster, Clam, and other Common Mollusks. By Alpheus 
Hyatt. Boston, 1884, 12mo., 65 pp., many figures. 
On the Rate of Growth of the Common Clam, etc. By John 
A. Ryder. Bulletin U. S. Fish Commission, Vol. V., 
1885, "pp. 174-176. 
On the Green Coloration of the Gills and Palps of the Clam 
(Mya arenaria). By John A. Ryder. Bull. U. S. F'ish 
Commission, Vol. V., 1885, pp. 181-185. 
The Clam Fisheries. Fishery Industries of the U. S., Sect. 
V., Vol. II., pp. 581-594. 
24. Mya truncata Linnaeus. 
[Mya, perhaps the ancient mus ; truncata, cut short.] 
British Gaper. 
Distribution, (a) General; — Low-water mark to below 
one hundred fathoms. Cape Cod to Greenland. North 
European seas to Great Britain. 
(b) In Acadia ; — (in N. B.) Grand Manan, low- water mark, 
Stimpson . Shediac, Whiteaves. Not abundant on the south- 
ern coast. (In N. S.) Halifax Harbor, not uncommon, Jones . 
Not reported from Prince Edward Island. Probably not 
abundant on our coast. 
Habits. This species may be distinguished from the common 
Clam {Mya arenaria ), by the shape of the valves, for in it the posterior 
■end, or end from which the tubes protude, is cut sharply off, as its name 
signifies, and is not evenly rounded as in Mya arenaria. The posterior 
end also, even when the shell is closed, gapes widely open, instead of 
■only slightly as an Mya arenaria; whence comes the name, given above, 
by which it is known in England. The epidermis is prolonged into a 
tube posteriorly helping to give the protection which is lost by the 
truncation of the shell. It is from two to tlu’ee inches in length. In its 
ihabits it is not known to differ essentially from Mya arenaria , 
Economics. It is probable that this species is often dug 
with and used for the same purposes as Mya arenaria. Indeed, 
as both are variable in form they frequently are much alike, 
and it is not probable that they are ever separated by the 
