THE EVOLUTION OF MAN 



it with a view to the great line of our evolution, 

 man emancipated himself from the stage of water 

 animals. 



Now that we have found that Ceratodus is 

 the living representative of another "bridge/' or 

 at least one side of it, we are naturally anxious 

 to find the other pillar of that bridge. That is to 

 say, we should like to know what other species 

 of fish helped to make this bridge, for there is a 

 wide difference between fish and fish. 



When we mention fish to a layman, his first 

 thought is of those kinds which he finds on his 

 table and with which, under the present condi- 

 tions of natural education, he is more familiar 

 than with zoological literature. The overwhelm- 

 ing majority of table fish consists of so-called 

 "bony fish," that is to say, all of them have a more 

 or less solid skeleton. All of the European river 

 fish belong to this class, the trout, the pike, the 

 carp, etc., and such sea fish as flounder, herring 

 and codfish. If we find a jar of delicious caviar 

 on our table, or if our meal is crowned with ex- 

 pensive Russian sterlet, we meet another group 

 of fish, the so-called Ganoids. The proudest rep- 

 resentative of this class is the sturgeon, the eggs 

 of which are used as caviar. These Ganoids are 

 especially distinguished by the fact that some of 



104 



