THE MUSCLES OP THE HORSE. 353 



and is flattened from side to side rather than from before 

 backwards (Fig. 93 B, 94 B). 



As might, be expected, the principal peculiarities of the 

 muscular system of the Horse are to be observed in the 

 limbs. 



The serratus magnus and the levator anguli scapulae (which 

 really form one miiscle), together with a sterno-scapularis, 

 form the great sling already mentioned, by which the weight 

 of the fore part of the body is transmitted to the anterior 

 extremities. The power of abduction is hardly needed by 

 a purely cursorial animal ; hence the deltoid is reduced 

 to its scapular portion, which is very small. On the other 

 hand, the pro- and re-tractors, the flexors and extensors, are 

 well developed. The supra- and infraspinatus are large. 

 There is a great cephalo-hurneralis, answering to the clavi- 

 cular portions of the human stemomastoid and of the 

 deltoid, which run into one another, in consequence of the 

 total absence of the clavicle. The anterior portion of the 

 stemomastoid is fixed to the mandible, and thus becomes 

 " sternomaxillary." 



The latissimus dorsi and teres muscles are very large, as 

 are the flexors and extensors of the antibrachium. 



The supinators and pronators are wanting ; but there is 

 a distinct extensor minimi digiti, the tendon of which unites 

 with that of the extensor communis. Radial and ulnar 

 extensors of the carpus are also present. The flexor per- 

 foratus has only a single tendon, which splits, and is attached, 

 as usual, to the sides of the middle phalanx. The flexor per- 

 forans also has only a single tendon, which pierces the 

 former, and is inserted into the lesser sesamoid and the 

 distal phalanx. 



The interossei of the third digit are represented only by 

 the ligaments which connect the gi-eater sesamoid bones 

 with the metacarpal, and in which a few muscular fibres are 

 sometimes found. There are said to be two others, one for 

 each lateral metacarpal, and a lumbricalis. 



In the hind limb, the femoral muscles are in the Horse 

 the same as in Man, but enormously developed. There is 



2 A 



