LEAVE MANAOS. 347 
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, Gurupa, Tajapuru, and Para. As far as 
these comparisons have gone, they show that the distinct 
faunae of the above-named localities are not the result of 
migrations ; for not only have different fishes been found 
in ah 1 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 indis- 
criminately, in deep and shoal waters. Should it prove that 
at Para, as well as at the intervening stations, after an in- 
terval of six months, the fishes are throughout the same as 
when we ascended the river, the evidence against the sup- 
posed 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 Para ; and so are a few other 
species more or less extensively distributed over what may 
be considered distinct ichthyological faunae. 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 cir- 
cumscribed within comparatively narrow limits. Though 
most quadrupeds of the United States, for instance, differ 
