THE ECONOMIC MOLLUSCA OF ACADIA. 
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and it may then be seen that the entering water must bathe the four 
great, flat gills as it passes downwards towards the mouth. These gills 
subserve the same function as do those of fishes, for in them the blood 
of the animal receives its needful oxygen and gives off its useless gases. 
Near the extreme anterior (though lower) end, guarded by four long 
ear-like flaps, is the minute mouth, and into it are guided by the flaps 
the minute animals, plants and Crustacea upon which it feeds. The 
water, now robbed of its oxygen and food materials, passes along the 
back or hinge side, taking up useless matters given off by the animal 
and passes out through the other tube. These tubes have the power of 
great extension, so that when their owner is safe deep in its burrow, it 
can push them up to the surface and get clear, pure water At low 
water, when the flats are exposed, it retains water enough to last until 
the tide covers it again, when, doubtless hungry enough, it keeps up an 
active in and out circulation of water. If it is incautious enough to 
come to the surface, it is likely to be snapped up by some fish, for 
many of this tribe dearly love the Clam. It also lives under many 
fathoms of water, where its habits are probably the same. Its time of 
reproduction has not been studied carefully in our waters, but probably 
does not differ greatly from that of the same species farther south, 
Mr, Ryder (see paper referred to below) finds that they give out their 
eggs from the tenth of September to the middle of October, The 
young are without shells and can swim freely about for a time, a 
provision to allow them to be removed from the vicinity of their 
parents, and so to prevent overcrowding. They soon settle to a sand 
or mud bottom and as they develop the shell, burrow beneath the 
surface. They grow to a length of from one to two inches in seven 
months, these lengths being exclusive of the tubes. The artificial 
raising of the young is considered very difficult, though they may be 
transplanted readily to new beds. 
Economics. This species has two very important uses — 
as human food and as bait in the fisheries. For the latter 
purpose it is very extensively used in Acadia, and also in the 
United States. Exact statistics of the quantity used for bait 
alone are wanting in the latter country, and the Dominion 
Fishery Returns probably give but an imperfect idea of the 
quantity used in the former. Nova Scotia is the only one of 
the Maritime Provinces which gives figures in the reports, 
which for the years from 1884 to 1887 are as follows: 
1884 750 barrels @ $7 = $5,250 
1885 1136 “ 5 5,680 
1886 970 “ 5 4,850+ ( 5100 a 7food USed ) 
1887 475 “ 7 3,325 
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