216 NOCTURNAL HOWLINGS. 
travellers had began to howl and seek refuge under 
their cots. Sometimes, after a long silence, the cry 
of the ferocious animal came from the tops of the 
trees, when it was followed by the sharp and long 
whistling of the monkeys. Humboldt supposes the 
noise thus made by the inhabitants of the thicket, 
at certain hours of the night, to be the effect of some 
contest that has arisen among them. pa 
On the 2d April they set sail before sunrise. 
The river was ploughed by porpoises, and the shore 
crowded with aquatic birds; while some of the latter, 
perched on the floating timber, were endeavouring 
to surprise the fish that preferred the middle of the 
stream. The navigation is rather dangerous, on ac- 
count of the large trees which remain obliquely fixed 
in the mud, and the canoe touched several times. 
Near the island of Carizales, they saw enormous 
trunks covered with plotuses or darters, and below 
it observed a diminution of the waters of the river, 
owing to infiltration and evaporation. Near the 
Vuelta de Basilio, where they landed to gather 
plants, they saw on a tree two beautiful jet-black 
monkeys of an unknown species, and also a nest 
of iguanas, which was pointed out by the Indians. 
The flesh of this lizard is very white, and, next to 
that of the armadillo, is the best food to be found 
in the huts of the natives. Towards evening it 
rained, and swallows were seen skimming along the 
water. They also saw a flock of parrots pursued by 
hawks. The night was passed on the beach. 
On the 3d they proceeded down the river in their 
solitary course. The sailors caught the fish known 
in the country by the nameof caribe; which, although 
only four or five inches in length, attacks persons 
