FISHES. 215 



CHAPTER XXI. 



FISHES continued. 



362. SOME fishes are fitted to live in fresh -water, and 

 some in salt, while others can live in both equally well. 

 Some remain in one place, but others are wandering ; and 

 some make long periodical journeys or migrations. At 

 the time for spawning or laying their eggs, fishes in the 

 sea generally either approach the coasts or go up the 

 rivers. The Herrings are an example of the former, and 

 the Shad and Salmon of the latter. In these migrations 

 the Salmon observe regular order, as the wild geese do 

 in theirs. They form two long files, united together in 

 front, and led by the largest female in the troop. The 

 males form the rear guard. When any obstacle opposes, 

 they leap over it, sometimes to the height of ten or even 

 sixteen feet. In this way they ascend rivers nearly to 

 their sources, and deposit their eggs in the autumn in 

 holes which they dig in the sand. Remaining here 

 through the winter, in the early spring they return to 

 the sea. It seems that the Salmon have the same instinct 

 that some birds have in regard to place, 212. This 

 was proved by a naturalist named Deslandes in this way. 

 He placed a ring of copper on twelve of these fish, and 

 set them at liberty in the River Auzou, in Brittany. 

 They, of course, emigrated, but the next year five of them 

 were caught in the same place, the second year three, 

 and the year after three more. 



363. Most fishes are abundantly prolific. You can see 

 this to be so if you observe the roe or spawn of any fish, 

 this being the collection of the eggs of the animal. It is 

 estimated that at least 60,000 eggs are contained in the 

 roe of a Herring. The roe of a Codfish was ascertained 



