INTRODUCTION. 5 
a movable rib, the other end of, which is attached to the breast- 
bone ; they follow next to the cervical vertebrz, while to them 
succeed the “lumbar” vertebrze which carry no complete ribs. 
The dorsal and lumbar segments vary in number, but together 
they rarely exceed seventeen. Behind these extend the ‘‘ sac- 
completely ossified together, and lastly, the 

ral” vertebrz 
bones of the tail or ‘‘ caudal” vertebrae, which may be many 
or few, according to the length of that appendage. 
The fore-limb is composed of three segments, the arm, fore- 
arm, and hand, together with a block by which it is attached 
to the side of the body. ‘To this block—the blade-bone or 
scapula—is articulated the arm-bone, or Aumerus, which at its 
elbow-joint hinges with the two bones, the #/na and the radius, 
of the fore-arm, on which in turn the hand is rotated. The hand 
is made up of three parts, the wrist-bones, or carpus, closely 
united together in two transverse rows with a central bone 
intervening between them ; next the elongated bones of the 
palm of the hand, or ~e¢acarpus, one to each finger, and lastly 
the phalanges, or finger-bones, three to each digit, except in the 
thumb, where there are but two. The hind-limb is formed on 
exactly the same plan. It has a connecting block—the pelvis ; 
giving suspension to the thigh, with its single bone, the /emzr, 
to which articulates the leg, with two bones (¢7dia and jbula), 
and the tripartite foot, composed of ¢arsus, metatarsus, and 
phalanges. 
Of the digestive organs of the Primates the teeth present 
very important characters, from the point of view of the classi- 
fication of the Order. They differ in form and number, and 
have distinct functions to perform. The teeth situated in front 
are the ¢ectsors and canines, sharp and pointed, for seizing, 
cutting, and holding the food. Behind them come the /re- 
