April 10th. We were unable to set sail until ten in the morning. It was hard to adapt to the new pirogue, which we saw as a new prison. To make it wider at the back of the boat we made branches into a kind of trellis, which stuck out on both sides. Unfortunately the leaf roof of this lattice-work was so low that you either had to lie down, and consequently saw nothing, or you had to stay hunched over. The need to transport pirogues across rapids, and even from one river to another, and the fear of giving too much hold to the wind by raising the toldo made this construction necessary for the little boats going up the Río Negro. The roof was designed for four people stretched Out on the deck or lattice-work, but your legs stuck far out, and when it rained half your body got wet. Worse still, you lie on oxhides or tiger skins, and the branches under the skins hurt you when you lie down. The front of the boat was filled with the Indian rowers, armed with 3-foot-long paddles in the form of spoons. They are all naked, sitting in twos, and row beautifully together. Their songs are sad and monotonous. The little cages with our birds and monkeys, increasing as we went on, were tied to the toldo and the prow. It was our travelling zoo. Despite losses due to accidents and sunstroke, we counted fourteen little animals when we came back from the Casiquiare. Every night when we established camp, our zoo and instruments occupied the middle; around them we hung our hammocks, then the Indians' hammocks and, outside, the fires we thought indispensable to scare off jaguars. At sunrise our caged monkeys answered the cries of the jungle monkeys.

The weather was cloudy, threatening one of those cloudbursts during which some 1 to 1. inches of rain may fall in a day. The sun shone on the tree-tops and, although we were not exposed to the rays, the heat was asphyxiating. Thunder rolled at a distance. The clouds hovered over the peaks of the high Guàcharo chain, and the plaintive howling of the araguatoes, heard so often in Caripe at sunset, announced the imminent storm. For the first time we had an opportunity to see those howler monkeys that belong to the family Alouatta (Stentor, Geoffroy), whose different species have long been confused by zoologists close at hand. While the small American sapajous, who imitate sparrow song with a whistle, have a simple, thin tongue bone, the large monkeys, the alouates and spider monkeys (Ateles, Geoffroy), have a tongue that rests on a large bony drum. The sad howling typical of the araguato is produced by air penetrating violently into this drum. I sketched these organs (59) on the spot as they are not well known to European anatomists. If you think about the size of the alouatta's bony box and the number of howler monkeys that can gather in one tree in the Cumanà and Guianan jungles, you will be less surprised by the force and volume of their united voices.