Puerto del Triunfo, Dept., Usulutan Dec., 28, 1923 - Jan., 25, 1924 Ateles Spider monkey - Mono Spider monkeys were common in the heavy jungle east of Puerto del Triumphs. They were usually encountered in bunches of two to twelve feeding on fruit in the trees. A bunch was frequently found in the same or immediate vicinity where they were seen the day before. Along one of the small jungle streams where I had a trapline I saw an adult male and female, and their tiny babe in the same tree every morning for one week, where they were feeding on fruit. When traveling through the trees the monkeys apparently knew exactly where they were going for they traveled at a rapid pace with their eyes on me half of the time. Thus they passed through the trees one after the other and each followed the same route taken by his predecessor. I have seen a string of adult monkeys pass through a tree and not vary more than twelve inches in the places where they grabbed and swung on the branches. Young ones or those as much as half grown frequently got off the trail when they are trying to watch me and escape at the same time. However I have watched young ones follow their elders when my presence wasn't