INTRODUCTION. 7 
The upper part of the windpipe is, in all Primates, modified 
to form the larynx, or organ of voice, constituted by fibrous 
strings stretched across its orifice, where they may be set in 
vibration by the air, in its passage to and from the lungs. 
The brain is relatively large in proportion to the body, and 
attains in the higher of the two sub-orders its most perfect 
development. The main brain (or cerebral hemispheres), when 
viewed from above, in size preponderates over, and conceals 
(except in the Lemurs) all the other parts of that organ. The 
surface of its lateral halves, which are connected by transverse 
bands so as to insure harmony of action between them, is 
marked by fissures and foldings, or convolutions, which vary 
in number and complexity, evidently in relation to the intel- 
ligence of the animal. The brain within the skull gives origin 
to the nerves for the chief organs of sense ; while from its pos- 
terior part it is continued along the back—within a canal 
formed by the neural arches of the vertebree—as the spinal 
column, from which arise the rest of the nerves for the 
body. 
The young of all the Primates are nourished in the mother’s 
womb by the passage of material from the blood-vessels of the 
parent through an organ known as the placenta. They are all 
born in a helpless condition, and remain unable to look after 
themselves for a considerable period, during which they are 
dependent on the milk secreted on the ventral surface of the 
mother by two or four glands, the teats or mammae—those 
characteristic organs from which the “Mammalia” have de- 
rived their name. These glands are present in both sexes, but 
are functional only in the female. 
We shall now proceed to describe more minutely the first of 
the two sub-orders of the Primates—the Lemur-like animals. 
