Fishes created where they now live. 31 



water fishes. Nevertheless, a minute investigation of all their spe- 

 cies has shown that Lake Superior proper, and the fresh waters 

 north of it, constitute in many respects a special zoological district, 

 sufficiently different from that of the lower lakes and the northern 

 United States, to form a natural division in the great fauna of the 

 fresh-water fishes of the temperate zone of this continent. 



We have shewn that there are types, occurring in all the lower 

 lakes, which never occur in Lake Superior and northwards, and that 

 most of the species found in Lake Superior are peculiar to it ; the 

 Salmonidse only taking a wider range, and some of them covering 

 almost the whole extent of that fauna, while others appear circum- 

 scribed within very narrow limits. 



Now, such differences in the range which the isolated species take 

 in the faunae, is a universal character of the distribution of animals ; 

 some species of certain families covering, without distinction, exten- 

 sive grounds, which are occupied by several species of other families, 

 limited to particular districts of the same zone. 



But after making due allowance for such variations, and taking a 

 general view of the subject, we arrive, nevertheless, at this conclu- 

 sion ; that all the fresh-water fishes of the district under examina- 

 tion are peculiar to that district, and occur nowhere else in any other 

 part of the w^orld. 



They have their analogues in other continents, but nowhere be- 

 yond the limits of the American continent do we find any fishes iden- 

 tical with those of the district, the fauna of which we have been re- 

 cently surveying. The lamprey eels of the lake district have very 

 close representatives in Europe, but they cannot be identified. The 

 sturgeons of this continent are neither identical with those of Europe 

 nor with those of Asia. The cat-fishes are equally different. We 

 find a similar analogy and similar differences between the perches, 

 pickerels, eelpouts, salmons, and carps. In all the families which 

 occur throughout the temperate zone, there are near relatives on the 

 two continents, but they do not belong to the same stock. And in 

 addition to these, there are also types which are either entirely pe- 

 culiar to the American continent, such as Lepidosteus and Percopsis, 

 or belong to genera which have not simultaneous representatives in 

 the two worlds, and are therefore more or less remote from those 

 which have such close analogues. The family of Percoids, for in- 

 stance, has several genera in Europe, which have no representatives 

 in America ; and several genera in America which have no represen- 

 tatives in Europe, besides genera which are represented on both con- 

 tinents, though by representatives specifically distinct. 



Such facts have an important bearing upon the history of crea- 

 tion ; and it would be very unphilosophical to adhere to any view 

 respecting its plan, which would not embrace these facts, and grant 

 them their full meaning. If we face the fundamental question which 

 is at the bottom of this particular distribution of animals, and ask 



