428 LOUIS AGASSIZ. 



tion. ... I have not neglected the opportu- 

 nity offered by the North River (the Hudson) 

 for the study of the fresh-water fishes of this 

 country. I have filled a barrel with them. 

 The species differ greatly from ours, with the 

 exception of the perch, the eel, the pike, and 

 the sucker, in which only a practiced eye could 

 detect the difference ; all the rest belong to 

 genera unknown in Europe, or, at least, in 

 Switzerland. . . . 



I was fortunate enough to procure also, in 

 the few days of my stay, all the species taken 

 in the lakes and rivers around Albany. Sev- 

 eral others have been given me from Lake 

 Superior. Since my return to Boston I have 

 been collecting birds and comparing them 

 with those of Europe. If M. Coulon could 

 obtain for me a collection of European eggs, 

 even the most common, I could exchange 

 them for an admirable series of the native 

 species here. I have also procured several in- 

 teresting mammals ; among others, two species 

 of hares different from those I brought from 

 Halifax, striped squirrels, etc. 



I will tell you another time something of 

 the collections of Boston and Cambridge, the 

 only ones in the United States which can rival 

 those of Philadelphia. To-day I have made 



