MON CHER AMI:—Je suis exténué de fatigue, mais je ne veux pas aller me reposer avant de vous avoir écrit un mot. Hier soir nous avons obtenu vingt-sept espèces de poissons à Gurupá et ce matin, cinquante-sept à Porto do Moz, en tout quatre-vingt-quatre espèces en moins de douze heures et, sur ce nombre, il y en à cinquante et une nouvelles. C’est merveilleux. Je ne puis plus mettre en ordre ce qu’on m’apporte au fur et à mesure que cela arrive; et quant à obtenir des dessins coloriés du tout, il n’en est plus question, à moins qu’à notre retour nous ne passions une semaine entière ici. Tout à vous, L. AGASSIZ.[54] _August 23d._—Yesterday morning, before reaching the little town of Gurupá, we passed a forest of Miriti palms; it is the first time we have seen a palm wood exclusive of other trees. In the afternoon we stopped at Gurupá and went on shore; but just as we landed, a violent thunder-storm burst upon us with sheets of rain, and we saw little of the town except the inside of the house where we took shelter. Mr. Agassiz obtained a most valuable collection of “forest fishes,” containing a number of new species; the Indians enumerate, however, some seventy distinct species of forest fishes in this vicinity, so that, notwithstanding his success, he leaves much to be done by those who shall come after him. We left during the night, and this morning we entered the river Xingu, stopping at Porto do Moz. The water is very blue and dark as compared with the muddy waters of the main river. Here Mr. Agassiz found two collections, one of forest fishes, the other of river fishes, awaiting him, Mr. Pimenta Bueno having sent messengers by the last steamer to a number of ports, desiring that collections should be in readiness for him. The harvest of this morning, however, was such an one as makes an era in the life of a naturalist, for it contained forty-eight new species,—more, Mr. Agassiz said, than it had ever fallen to his lot to find in the course of a single day. Ever since we entered the Amazons the forest seems to me, though more luxuriant, less sombre than it did about Rio. It is more transparent and more smiling; one sees into it, and sees the sunshine glimmering through it and lighting up its depths. The steamer has just left behind the first open land we have passed,—wide, extensive flats, with scarcely a tree, and covered with thick, coarse grass.