18 THE ECONOMIC MOLLUSCA OF ACADIA. 



elevation of the land in this region threw the Labrador current 

 off from the coast and allowed the water inside the Banks, 

 then near the surface, to become warmed up in summer, as it 

 is to-day in the Gulf of St. Lawrence. These forms then 

 crept northward and all the coast from Virginia to Newfound- 

 land was occupied by them. The land is now sinking; cold 

 currents are coming back to our shores and the southern 

 animals cannot hold their own against the northern, which 

 are better fitted for the new conditions. It is probable that 

 ultimately all of these southern forms will become extinct in 

 the Gulf, but the time is so remote that the practical man 

 need not take it into his calculations. 



It should be hardly necessary to call attention to the fact 

 here, that there is yet very much to be learned about the 

 distribution of Molluscs and other animals upon our shores; 

 about their habits, their relations to other animals, their use- 

 fulness and noxiousness to man. Even in the matter of their 

 value and palatableness as food there is much need of informa- 

 tion. There is an abundance of work for every observer to 

 do, and teachers who interest themselves and their pupils in 

 such subjects will be repaid many fold, not only by the facts 

 observed and training acquired, but by their further initiation 

 into the spirit of nature and their refreshment by the pure 

 air of new fields, both figurative and literal. 



In the following list, the nomenclature adopted is not in 

 all cases that of the latest authorities, though such names are 

 always given in the synonymy. The scientific name given 

 first is usually that of Binney's Edition of Gould's Invertebrata 

 of Massachusetts, though in certain instances where the latter 

 is clearly erroneous, as in the Cephalopods, those of other 

 writers are followed. The work mentioned is the only one 

 extant which gives an account of our Mollusca, and, unfor- 

 tunately, is rare and expensive, though it is to be found in 

 most scientific libraries. Those who wish scientific descrip- 

 tions and figures should turn to it, and there they will find 

 references to other works of importance. The list of works 

 given below ijicludes only those consulted in the preparation 

 of this paper. 



