THE LIMBS. 165 



articulation (Fig. 6, s), and a single large, transversely 

 extended one (Fig. 6, s 1 ), called the " navicular " bone, 

 behind the joint formed between the second and third 

 phalanges. 



In standing at rest in the natural position the 

 forearm and the metacarpus are nearly upright, and 

 the three bones of the digit or finger form a nearly 

 straight line with them, but inclining forwards at 

 the lower end. The third, or ungual phalanx, alone 

 rests, through the intermedium of the hoof, upon the 

 ground, and receives the whole of the weight of one 

 quarter of the animal's body. 



The main peculiarities of the skeleton of the fore 

 limb of the horse are these : the absence of clavicle, 

 the elongated, narrow and flat scapula, the short and 

 obliquely placed humerus, the consolidated radius 

 and ulna, the immensely developed middle metacar- 

 pal and its digit, and the suppression of all the 

 others. Moreover, all the joints from the shoulder 

 downwards are simply hinge-joints, allowing free 

 fore-and-aft flexion and extension, but scarcely any 

 movement in any other direction. 



COMPARISON OF THE SKELETON OF THE HIND LIMB 

 OF THE HORSE WITH THAT OF MAN. 



The pelvic differs essentially from the pectoral 

 girdle, inasmuch as it is firmly fixed to the trunk, to 



