r_ _Sub-orders_ _Families_

,- a. PROSIMII (Lemurs and Aye-Ayes)
|
| ,- i. Hapalidae (Marmosets)
| | ii. Cebidae (Howling Monkeys,
PRIMATES -+ | Tee Tees, Squirrel Monkeys,
| | Spider Monkeys, and Capuchin
| | Monkeys)
`- b. ANTHROPOIDEA ... -+ iii. Cercopithecidae (Baboons
| and Macaques)
| iv. Simiidae (Gibbons, Orangs,
| Chimpanzees, and Gorillas)
`- v. Hominidae (Man)

When we turn to the science of genetics we meet a similar condition, for
the literature reveals only scattered bits of information concerning
heredity in the primates. No important experimental studies along
genetic lines have been made with them, and such general observations
from nature as are on record are of extremely uncertain value. Were one
to insist that we know nothing certainly concerning the relation of
heredity in other primates than man, the statement could not well be
disputed.

Occasionally in recent years students of human diseases have employed
monkeys or apes for experimental tests, but aside from the isolated
results thus obtained, extremely little is known concerning the diseases
peculiar to the various types of infra-human primates or the significant
relations of their diseases to those of man.

Next in order of extent to our morphological knowledge of these
organisms is that of their behavior, mental life, and social relations.
But certainly no one who is conversant with the behavioristic,
psychological and sociological literature could do otherwise than
emphasize its incompleteness and inadequacy. For our knowledge of
behavior has come mostly from naturalistic observation, scarcely at all
from experimentation; our knowledge of social relations is obviously
meager and of uncertain value; and finally, our knowledge of mind is
barely more than a collection of carelessly drawn inferences.

This picture of the status of scientific work on the primates, although
not overdrawn, will doubtless surprise many readers, and even the
biologist may find himself wondering why we are so ignorant concerning
the lives of the organisms most nearly akin to us, and naturally of
deepest in