260 LAKE SUPERIOR. 



associate it with any of the types of living fishes, nor succeed in 

 finding, among living types, any one to associate fairly with it. It 

 was a fact, at once deeply impressed upon my mind, that it stands iso- 

 lated among all living beings ; and this early impression has gradually 

 led me to the views respecting classification which I have expressed 

 above, and which have frequently guided me in appreciating both 

 the various degrees of relationship, and also the differences which I 

 have noticed among different families ; and, I may say, has also kept 

 me free from fanciful attempts at symmetrical classifications. 



Somewhat later, my investigations of the fossil fishes led me to 

 the distinct appreciation of the great difference there is between the 

 characters of the class of fishes in early geological ages ; I also 

 noticed that all the bony fishes of former ages are more or less 

 allied to the gar-pike, and widely different from the types of 

 fishes now prevailing. But the real nature of this difference was 

 only gradually understood. I had not yet perceived that the fishes 

 of older times had peculiar characters of their own, not to be 

 found either among the more recent fossils or among the liv- 

 ing representatives of that class. But the opportunity of study 

 ing the skeleton of Lepidosteus, which was afforded me in Paris by 

 Cuvier, showed at once, that these fishes have reptilian characters.* 



The articulation of their vertebrae differs from that of the verte- 

 brae of all other fishes no less than the structure of their scales. 

 Their extremities, especially the pectoral limbs, assume a higher 

 development than in fishes generally. Their jaws also, and the 

 structure of their teeth, are equally peculiar. Hence, it is plain 

 that, before the class of reptiles was introduced upon our globe, 

 the fishes, being then the only representatives of the type of verte- 

 brata, were invested with the characters of a higher order, embody- 

 ing, as it were, a prospective view of a higher development in 

 another class, which was introduced as a distinct type only at a 

 later period ; and from that time the reptilian character, which had 

 been so prominent in the oldest fishes, was gradually reduced, till, 

 in more recent periods, and in the present creation, the fishes lost in 



* For further details, see my Recherches sur les Poissons Fossiles, Vol. II. part 2, 

 p. 173. 



