The =pectoral girdle= lies external to the ribs, and has no bony attachment to the axial skeleton. In almost all Mammalia it is, as compared with that in Sauropsids, very incomplete; and in the dog it is even more reduced than in the majority of Mammalia. The dorsal portion or =scapula= is well developed, but the ventral portion is almost entirely absent. The =scapula= is somewhat triangular in shape, the apex being directed downwards and forwards, and being expanded to form the shallow =glenoid cavity= with which the head of the humerus articulates. The inner surface of the scapula is nearly flat, while the outer is drawn out into a very prominent ridge, the =spine=, which, arising gradually near the dorsal end, runs downwards, dividing the surface into two nearly equal parts, the =prescapular= and =postscapular fossae=, and ends in a short blunt process, the =acromion=. The anterior border of the scapula is somewhat curved, and is called the =coracoid border=; it is terminated ventrally by a slight blunt swelling, the =coracoid process=, which ossifies from a different centre from the rest of the scapula, and is probably the sole representative of the =coracoid=. The dorsal or =suprascapular border= of the scapula is rounded, while the posterior or =glenoid border= is nearly straight. The clavicle[144] or collar bone, which in a large proportion of mammals is well seen, in the dog is very imperfectly developed; it is short and broad, and is suspended in the muscles, not reaching either the scapula or sternum. THE ANTERIOR LIMB. The anterior limb of the dog is divisible into the usual three portions, the =brachium= or =upper arm=, the =antibrachium= or =fore-arm=, and the =manus= or =wrist= and =hand=. The =brachium= or =upper arm= includes only a single bone, the =humerus=.