FIGURE 9.--Skirrl using a saw.



All of the animals except the orang utan had been used more or less for
experiments on behavior by Doctor Hamilton, but this prior work in no
way interfered with my own investigation. Doctor Hamilton has
accumulated a large mass of the most valuable and interesting
observations on the behavior of monkeys, and he more thoroughly
understands them than any other observer of whom I have knowledge. Much
to my regret and embarrassment in connection with the present report, he
has thus far published only a small portion of his data (Hamilton, 1911,
1914). In his most recent paper on "A study of sexual tendencies in
monkeys and baboons," he has given important information concerning
several of the monkeys which I have observed. For the convenience of
readers who may make use of both his reports and mine, I am designating
the animals by the names previously given them by Hamilton. The
available and essential information concerning the individuals is
presented below.



_List of animals in collection_

Skirrl. _Pithecus irus_. Adult male.

Sobke. _P. rhesus_. Young adult male.

Gertie. _P. irus-rhesus_. Female. Born November, 1910.