264 COMPARATIVE MYOLOGY. 



external scapular region. Anteriorly the parts unite, and the muscle expands 

 over the face, joining its fellow of the opposite side. 



The Head. 

 The levator labii superioris alceque nasi, dilatator naris transversus, and lachry- 

 malis are wanting, but the nasalis longus is well developed. The retrahens 

 exlernus has two tendons of insertion, one proceeding to the conchal, the other 

 to the scutiform cartilage. 



The Trunk. 



The inferior portion of the levator humeri is attached by one tendon to the 

 occipital protuberance, and by a second to the mastoid crest, the superior 

 portion going to the wing of the atlas. ^ 



The sterno-thyroideus is double, having two attachments to the thyroid 

 cartilage. The longus colli, instead of being a single muscle as in the horse, is 

 separable into right and left portions. The scalenus extends far backwards, 

 usually reaching the third rib. 



In the costal region we have merely to note that the trapezius is largely 

 developed ; the latissimus dorsi is also large, and presents digitations by which 

 it becomes attached to the ribs it covers. 



The pectoral muscles resemble those of the ox. In the dorso-lumbar region 

 we find that the longissimus dorsi is divisible into a transverse and a costal 

 portion. 



The abdominal tunic is a mere fold of cellulo-fibrous membrane, while the 

 obliquus externus presents a large fleshy, and a small, or rather narrow, 

 aponeurotic portion. In the sublumbar region the muscles of the omnivora, 

 like those of the ruminants, present no features worthy of comparison with 

 those of the horse ; the diaphragm also calls for no special comment. 



Pectoral Limb. 



The/ea;or brachii at its insertion gives off a tendon which passes to the ulna, 

 and is attached to the lower part of the olecranon, and close by is attached 

 another slip from the humeralis obliquus. The coraco-humeralis is short, very 

 tendinous, and consists of only one portion, which is inserted just above the 

 insertion of the teres internus. The scapulo-ulnaris is continuous with the 

 latissimus dorsi. The extensor metacarpi magnus is inserted to the inner large, 

 the obliquus to the inner small metacarpal bone. The extensor communis tendon 

 divides into four parts, one being attached to either distal phalanx ; and the 

 extensor proprius internus tendon bifurcates, and goes to the distal phalanges of 

 the two inner digits, the proprius externus joining the two outer ones in a 

 similar manner. The fiexor pedis perforatus is double, both as to its fleshy 

 portion and its tendon ; a part becomes inserted to the median phalanx of each 

 of the large digits, while the tendon of the flexor perforans divides into four 

 parts, one being inserted to each distal phalanx. 



In the metacarpal region there are four interossei or interosseous palmar 

 muscles, which arise superiorly from the back of the metacarpal bones and 

 ligaments, and terminate each in two small sesamoid tendons, which afterwards 



