SKIN MARKINGS AND CALLOSITIES OF THE HORSE 499 



the light spots are singularly suggestive of the plates on the carapace of 

 a large armadillo. In fact, the markings are exactly what would be 

 expected to remain if the armour-plates became loose and ultimately fell 

 off, leaving on the skin only the impression of their outlines. 



No proof of such a change having taken place in the course of ages can 

 be offered, probably none exists, but it may at least be urged that there 

 would be nothing very remarkable in the change, given that the doctrine 

 of evolution is true. On this point Dr. Bonavia remarks that it would be 

 as idle to suppose that the bony plates of the armadillo, the hide plates of 

 the rhinoceros, and the picture plate of the horse are all so like each other 

 by mere accident, as it would be to suggest that the seven cervical vertebrae 

 or neck bones, which they possess in common, came to them by chance. 



Markings on the face of the horse, before referred to, in the varied forms 

 of the so-called hlaze or race, which are always present to a greater or a 

 less extent, varying in size and in colour, can be accounted for on the same 

 principle, as also may similar patches of colour or absence of colour in other 

 parts of the body, round the eyes, on the nose, and on the lower parts of the 

 extremities. And it is also the case that the upper portions of the body are 

 commonly of a darker colour than the under portions. All these variations, 

 according to Dr. Bonavia, may be explained, if his theory that the horse is 

 descended from an armour-plated ancestor is correct. The lighter colours 

 would indicate the parts from which the armour-plates had first disappeared, 

 leaving only the pictures behind them, and it would naturally happen that 

 the most movable parts, or those most subject to friction, would iirst get 

 free from the hard plates which, while they protected the parts they covered, 

 would at the same time impair their motion. Thus the eyelids, the limbs, 

 and the terminal extremities would be most likely to be freed earlier than 

 the upper parts of the l)ody, and on the same principle the friction which the 

 abdominal region would suffer, when the animal was lying on the ground, 

 would tend to assist the removal of the armour. The fact of the front 

 of the head being most exposed to rubbing against branches of trees and 

 other projecting bodies would account for loss of armour from that part. 



That the process of removal of the armour-plates must have been a 

 gradual one, originated and modified by changes in the conditions of life, 

 cannot be doubted; and, in addition, natural selection, absolutely unchecked 

 by any restraining influences, would inevitably conduce to various altera- 

 tions in the size and the shape of the picture-markings, exactly as artificial 

 selection does in the present day, with the recognized exceptions which from 

 time to time upset the breeder's calculations through the operation of the 

 law of atavism, or reversion to some ancestral type. It does not, however, 

 at all times occur to the breeder so strongly as it might, that a red calf, or 



