DOWN THE AMAZONS. 375 
his voyage up the river, he had had some conversation respect- 
ing the scientific objects of his visit to the Amazons, has made 
during our absence one of the finest collections obtained in 
the whole course of our journey, containing, in separate lots, 
the fishes from above and below the cascade. By means of 
this double collection, which Mr. Agassiz has already exam- 
ined carefully, he ascertains the fact that the fauna3 on either 
side of the falls are entirely distinct from each other, as are 
those of the upper and lower courses of the Amazons, and also 
those of its tributaries, lakes, and igarapes. This is a most 
important addition to the evidence already obtained of the 
distinct localization of species throughout the waters of the 
Amazonian Valley. We regretted that, on account of the 
absence of Senor Vinhas from the town, we could not thank 
him in person for this valuable contribution. Finding that the 
efforts of this gentleman had really left nothing to be done 
in this locality, unless, indeed, we could have stayed long 
enough to make collections in all the water-basins connected 
with the Xingu, we left early in the morning and reached 
Gurupa yesterday. This little town stands on a low cliff 
some thirty feet above the river. On a projecting point of 
this cliff there is an old, abandoned fort ; and in the open 
place adjoining it stands a church of considerable size, and 
seemingly in good repair. But the settlement is evidently 
not prosperous. Many of its houses are ruinous and de- 
serted, and there is even less of activity in the aspect of the 
place than in most of the Amazonian villages. We heard 
much of its insalubrity, and found very severe cases of inter- 
mittent fever in one or two of the houses we entered. While 
Mr. Agassiz made a call upon the subdelegado, who was 
himself confined to his room with fever, I was invited to rest 
in the open veranda of a neighboring house, which looked 
