DOWN THE AMAZONS. 375 



his voyage up tho 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 faunas 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 



