INTRODUCTION. 5 



a movable rib, the other end of which is attached to the breast- 

 bone ; they follow next to the cervical vertebrae, while to them 

 succeed the "lumbar" vertebrae which carry no complete ribs. 

 The dorsal and lumbar segments vary in number, but together 

 they rarely exceed seventeen. Behind these extend the "sac- 

 ral" vertebrae — completely ossified together, and lastly, the 

 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 hu?nerus, which at its 

 elbow-joint hinges with the two bones, the ulna 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 metacarpus, one to each finger, and lastly 

 \hQ phala?tges, 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, ^t femur ^ 

 to which articulates the leg, with two bones {^Hbia and fibula), 

 and the tripartite foot, composed of tarsus^ 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 incisors and canines, sharp and pointed, for seizing, 

 cutting, and holding the food. Behind them come the pre- 



