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 vertebrae — 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 mammce. — 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. 



