“Keeping in view all the information I could obtain upon this subject, I have attempted, wherever it was possible to do so, to make collections simultaneously at different points of the Amazons: thus, while I was collecting at Villa Bella six months ago, some of my assistants were engaged in the same way at Santarem, and higher up on the Tapajoz; while I was working at Teffé, parties were busy in the Hyavary, the Iça, and the Hyutahy; and during my last stay at Manaos, parties have been collecting at Cudajas and at Manacaparu, and higher up on the Rio Negro, as well as at some lower points on the main river. At some of these stations I have been able to repeat my investigations at different seasons, though the intervals between the earlier and later collections made at the same localities have, of course, not been the same. Between the first collections made at Teffé and the last, hardly two months intervened, while those made on our first arrival at Manaos in September up to the present time cover an interval of four months; from the first to the last at Villa Bella more than five months will have elapsed. On this account I attach great importance to the renewal of my investigations at that place, as well as to the later collections from Obydos, Santarem, Monte Alegre, Porto do Moz, Gurupá, Tajapurú, and Pará. As far as these comparisons have gone, they show that the distinct faunæ of the above-named localities are not the result of migrations; for not only have different fishes been found in all these basins at the same time, but at different times the same fishes have been found to recur in the same basins, whenever the fishing was carried on, not merely in favored localities, but as far as possible over the whole area indiscriminately, in deep and shoal waters. Should it prove that at Pará, as well as at the intervening stations, after an interval of six months, the fishes are throughout the same as when we ascended the river, the evidence against the supposed extensive migrations of the Amazonian fishes will certainly be very strong. The striking limitation of species within definite areas does not, however, exclude the presence of certain kinds of fish simultaneously throughout the whole Amazonian basin. The Pirarucu, for instance, is found everywhere from Peru to Pará; and so are a few other species more or less extensively distributed over what may be considered distinct ichthyological faunæ. But these wide-spread species are not migratory; they have normally and permanently a wide range, just as some terrestrial animals have an almost cosmopolite character, while others are circumscribed within comparatively narrow limits. Though most quadrupeds of the United States, for instance, differ from those of Mexico and Brazil, constituting several distinct faunæ, there is one, the puma or red lion, the panther of the North, which is found on the east of the Rocky Mountains and the Andes, from Patagonia to Canada.