Elizabeth Cary Agassiz, Louis Agassiz: his life and correspondence, third edition

[428] . . . I have not neglected the opportunity 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. Several 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 interesting 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