VI. 



FISHES OF LAKE SUPERIOR COMPARED WITH THOSE OP 

 THE OTHER GREAT CANADIAN LAKES. 



Besides the interest there is everywhere in studying the living 

 animals of a new country, there is a particular interest to a natural- 

 ist in ascertaining their peculiar geographical distribution, and their 

 true affinities with those of other countries. It is only by following 

 such a course, that we can hope to arrive at any exact results as to 

 their origin. In this respect the freshwater animals have a peculiar 

 interest, as from the element they inhabit, they are placed under 

 exceptional circumstances. 



Marine animals, as well as those inhabiting dry land, seem to have 

 a boundless opportunity before them to spread over large parts of the 

 earth's surface, and their locomotive powers would generally be suf- 

 ficient to carry them almost anywhere ; but they do not avail them- 

 selves of the possibility ; notwithstanding their facilities for locomo- 

 tion, they for the most part remain within very narrow limits, using 

 their liberty rather to keep within certain definite bounds. This 

 tendency of the higher animals especially, to keep within w^ell-ascer- 

 tained limits, is perhaps the strongest evidence that there is a natural 

 connection between the external world, and the organized beings 

 living upon the present surface of our globe. The laws which regu- 

 late these relations, and those of geographical distiibution in partic- 

 ular, have already been ascertained to a certain extent, and will 

 receive additional evidence from the facts recorded during our jour- 

 ney. 



The freshwater animals are placed in somewhat different circum- 

 stances. Their abode being circumscribed by dry land within limits 



