INTRODUCTION. 



It is proposed to give, in the following- pages, a brief account of the 

 economic mollusca of the United States, together with a description of 

 the manner of conducting the various fisheries and their dependent 

 industries. Minute detail of matter, whether of biological or economic 

 interest, is not attempted; the design is to supplement the molluscan 

 exhibit by an explanatory pamphlet, which will be illustrated by the ob- 

 jects exhibited. The information given is obtained chiefly from Profes- 

 sor Verrill's papers on the Invertebrates of Vineyard Sound, published 

 in the Eeport of the United States Commissioner of Fish and Fisheries, 

 and from the advance sheets of the Eeports of Mr. Ernest Ingersoll on 

 the Shell-Fish Industries of the United States, published by the Census 

 Bureau. Many other authorities, too numerous to mention, have also 

 been consulted. 



The total annual product of the shell-fish industries of the United 

 States amounts to 24,859,044 bushels, valued at $14,629,187. This total 

 is divided among the various fisheries according to the following table : 



Name. 



Oyster fishery . . 

 Clam fishery' . . . 

 Mussel fishery.. 

 Scallop fishery.. 

 Abalone fishery 



Number 

 bushels. 



22, 195, 370 



1, 955, 580 



600, 000 



108, 094 



Value. 



$13, 438, 852 



996, 305 



37, 500 



28, 825 



127, 705 



While the oyster industry, on account of its importance, deserves the 

 most and first attention, yet, as the collection on exhibition is part of 

 that of the National Museum, it is deemed best to maintain the original 

 systematic arrangement, and therefore the most highly organized of tlie 

 the mollusca, the Cephalopods are first considered. 



MOLLUSCA CEPHALOPODA. 



The most recent authorities assign thirty species of cephalopods to 

 the fauna of the eastern coast of North America. While so numerously 

 represented, however, only a few of the species are found in sufficient 

 abundance to make them of commercial value. These comprise Ommas- 

 trephes illecebrosa, Loligo pealii, Loligo brevis, and the gigantic squids 

 (Architeuthis) of Newfoundland and adjacent coasts; of these, the most 

 abundant and widely distributed is 



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