THE ECONOJIIC MOLLUSCA OF ACADIA. 17 



■an absolute right to the products of their labor and protection 

 from trespassers, but even, if necessary, positive encouragement 

 in the way of bounties, until Oyster-culture shall become an 

 established industry of the Dominion. Canada does not now 

 produce more than a fraction of the Oysters she uses; it is 

 soon to become a question of deriving the greater part of her 

 supply frcm cultivated beds in the United States or from 

 •cultivated beds in Canada, for the natural beds of the United 

 States are rapidly becoming exhausted, and attention is being 

 directed towards culture. 



Something should be said here as to the distribution of 

 Molluscs in our waters. It will be noticed by those who read 

 the following pages, that many forms are spoken of which 

 occur in the Gulf of St. Lawrence and not elsewhere north of 

 •Cape Cod; others occur in the Bay of Fundy, the distribution 

 of which is circumpolar or arctic. These are two among very 

 many facts which indicate a curious distribution of animal 

 life in Acadian waters. In the southern part of the Gulf, all 

 along the North Shore of New Brunswick and Nova Scotia 

 and all around the coast of Prince Edward Island and Cape 

 (Breton, occur animals of species identical with those living to 

 the south of Cape Cod, and in most cases they do not occur 

 in numbers between those localities. The Oyster, Quahog, 

 Drill {Urosalpinx), Plicated Mussel, are all examples of this, 

 and many others might be mentioned which do not fall with- 

 in the limits of this paper. In the Bay of Fundy and on the 

 •coast of Nova Scotia, south of Chebucto Bay, on the other 

 hand, the forms are decidely northern, the uniformly cold 

 water of that region not allowing of the development of the 

 young of such southern forms as can thrive in the Gulf. In 

 the latter, the shallow waters, little disturbed by tides, can 

 become very warm during the summer, and favorable con- 

 ditions thus being provided for the young, the adults survive 

 them in spite of the cold of winter. For the origin of this 

 condition of affairs we must look to geological causes, the 

 discussion of which is not in place here. The substance of it 

 lis, that in times recent geologically (certainly post-glacial), an 



