208 THE SCIENTIFIC RESULTS OF V 



It is apparent, tlien, that tlie results of zoological 

 science, as they may possibly affect fisheries, must 

 even at the j^resent moment be very considerable. 

 We may classify them as follows: — 



I. The discrimination and classification of the 

 diff'erent kinds of plants and animals, including the 

 fishes themselves which inhabit the various fresh and 

 sea waters where fisheries are carried on. This is 

 what is known as the study of Systematic Zoology, 

 and of the fauna and flora of districts. 



II. The knowledge of the successive phases of 

 development or growth from the egg, and of the 

 internal anatomy and mechanism of life of the chief 

 forms of such animals and plants. This constitutes 

 what is known as General Morphology and Physi- 

 ology. 



III. A specially detailed knowledge of the life- 

 history of those species of fishes, molluscs, and Crust- 

 acea, which are valuable to man and are the subject 

 of fisheries ; a knowledge of their migrations, suscepti- 

 bility to external influences, of their food and its 

 history in detail ; of their enemies, in the shape of 

 other fishes, birds, whales, seals, and insects, etc., 

 which prey upon them and their young ; a knowledge 

 of their parasites, injurious or harmless, and of their 

 diseases. Such knowledge may be termed the Special 

 Biology of Economic Fishes. 



IV. A knowledge of those particular features in 

 the life-history of an economic fish or mollusc, which 

 directly concern the work of the fisherman or the fish 

 culturist; a knowledge of the efi'ects produced by 



