On the Salmon Tribe. 145 



grow within the e^g very slowly for about two months before 

 they are hatched ; while fecundated eggs of some other fami- 

 lies which spawn in spring and summer, give birth to young 

 fishes a few days after they are laid. The SalmonidcR^ on the 

 contrary, are born at an epoch when the waters are generally 

 frozen up ; that is at a period when the maximum of tempera- 

 ture is at the bottom of the water, where the eggs and young 

 salmons remain among gravel, surrounded by a medium 

 which scarcely ever rises above thirty or forty degrees. 



It is plain from these statements, and from what we know 

 otherwise of the habits of this family, that there is no one 

 upon the globe living under more uniform circumstances, and 

 nevertheless the species are extremely diversified, and we 

 find peculiar ones in all parts of the world, where the family 

 occurs at all. Thus we find in Lake Superior species which 

 do not exist in the course of the Mackenzie or Saskatchawan, 

 and vice versa ; others in the Columbia river which differ from 

 those of the Lena, Obi, and Yenisei, while Europe again has 

 its peculiar forms. 



Whoever takes a philosophical view of the subject of Na- 

 tural History, and is familiar with the above stated facts, will 

 now understand why, notwithstanding the specific distinctions 

 there are between them, the trouts and white fishes are so 

 uniform all over the globe. It must be acknowledged that it 

 is owing to the uniformity of the physical condition in which 

 they occur, and to which they are so admirably adapted by 

 their anatomical structure, as well as by their instinct. 

 Running up and down the rapid rivers and mountain currents, 

 leaping even over considerable waterfalls, they are provided 

 with most powerful and active muscles ; their tail is strong 

 and fleshy, and its broad basis indicates that its power is 

 concentrated ; it is like the paddle of the Indian who propels 

 his canoe over the same waters. Their mouth is large, their 

 jaw strong, their teeth powerful, to enable them to secure 

 with ease the scanty prey with vvhich they meet in these 

 deserts of cold water ; and, nevertheless, though we cannot 

 but be struck by the admirable reciprocal adaptation between 

 the structure of the northern animals and the physical con- 

 dition in which they live, let us not mistake these adaptations 



VOL. XLIX. NO. XOVII. — .JULY 1850. K 



