1. head.9. proximal end of the radius.
2. lesser tuberosity.10. shaft of the radius.
3. greater tuberosity.11. olecranon.
4. shaft of the humerus.12. surface for articulation with
5. trochlea.the trochlea.
6. internal condyle.13. surface for articulation with
7. external condyle.the radius.
8. supra-trochlear foramen.14. distal end of the ulna.

In the young animal the ends of both radius and ulna are seen to ossify from centres different from those forming the shafts. The epiphyses forming both ends of the radius, and the distal end of the ulna are large, while that at the proximal end of the ulna is small, and forms only the end of the olecranon.

The Manus is divided into

a. The carpus or wrist, formed of a group of small bones.

b. The hand, which includes firstly some elongated bones, the metacarpals, forming what corresponds to the palm of the hand, and secondly the phalanges, which form the fingers.

The Carpus or wrist. The carpus of the dog consists of seven small bones, arranged in a proximal row of three, and a distal row of four. It differs much from the simpler type met with in the newt. The largest bone of the proximal row is the scapho-lunar (fig. 80, 1), formed by the fused scaphoid (radiale), lunar (intermedium), and centrale; it has a large convex proximal surface for articulation with the radius, and articulates distally with the trapezium, trapezoid, and magnum, and internally with the cuneiform. The cuneiform (ulnare) (fig. 80, 2) has a posterior rounded surface articulating with the ulna; it articulates in front with the unciform, and internally with the pisiform (fig. 80, 7), which is a comparatively large sesamoid bone on the ulnar side of the carpus. Frequently also there is a small sesamoid bone on the radial side of the carpus. The trapezium (carpale 1), trapezoid (carpale 2), and magnum (carpale 3) (fig. 80, 5) are all small bones, and support respectively the first, second, and third metacarpals. The unciform (carpalia 4 and 5) (fig. 80, 6) is larger, and supports the fourth and fifth metacarpals.

The hand has five digits, each consisting of an elongated metacarpal, followed by phalanges, the last of which, the ungual phalanx, is pointed and curved, and bears the claw. Each of the metacarpals is seen in the young animal to have its distal end formed by a prominent epiphysis, and each of the phalanges, except those bearing the claws, has a similar epiphysis at its proximal end.

The pollex (fig. 80, A, I ) is far shorter than the other digits, and normally does not touch the ground in walking. It has only two phalanges, while each of the other digits has three. A pair of small sesamoid bones are developed on the ventral or flexor side of the metacarpo-phalangeal articulations of all the digits except the pollex. Frequently similar sesamoid bones occur also on the dorsal side of the phalangeal articulations.

The Pelvic Girdle.

The pelvic girdle consists of two halves, which lie nearly parallel to the vertebral column.