General Introduction. 3 



crustaceans, soft or jelly fishes, the molluscs, down to those 

 creatures resembling live plants — the zoophytes or coral- 

 lines, which partake of the qualities of plant, animal, and 

 mammal. All these are peculiar to the sea or the fresh 

 waters ; and the ocean has its marine plants — seaweeds 

 which remain growing on the ground shoals, or rise to the 

 surface and then float. These, too, have many useful or 

 economic applications. 



It is not our purpose to speak of the inhabitants of the 

 ocean, generally, but only to restrict the investigation 

 to those which are of some use to man. 



Pliny enumerated but 94 species of fish ; Linnaeus in- 

 creased the number to 478 ; but recent naturalists have 

 described over 13,000 species, one-tenth of which confine 

 themselves to the fresh waters. 



The human race derives almost incalculable benefits 

 from them, as is evidenced by the extent and value of the 

 river, coast, and sea fisheries of the world. 



The sea, as Commander Maury well observes, has its 

 offices and duties to perform. So may its inhabitants ; con- 

 sequently he who undertakes to study its phenomena must 

 cease to regard it as a waste of waters. He must look 

 upon it as a part of the exquisite machinery by which the 

 harmonies of nature are preserved, and then he will begin 

 to perceive the developments of order and the evidence of 

 design, which make it a most beautiful and interesting 

 subject for contemplation. 



The harvest of the sea has not yet been attended to 

 and garnered to the same extent as the land. Some 

 nations, as the Chinese, have, it is true, long given close 

 attention to the profitable utilization of its commercial 

 products, and several European nations and the Americans 

 have also prosecuted certain fisheries ; but systematic 



