Eassie — Some Variations in the Skeleton of the Domestic Horse. '6'i^ 



bent outwards, the elbows and stifles being wider ajiart tliau tlie shoulders 

 and liip-joints (fig. 3 b). In this arrangement tliere is the advantage of 

 a very wide base of support, and consequently of greater stability. 



The parallelism of the limbs, and the forward direction of the bones and 

 joints is well illustrated in tlie skeleton of the girafFe in the Irish National 

 Museum, and in tliat of a young zebra in the same collection.' The latter 

 illustrates the points alluded to in an existing wild species of tlie same genus 

 as the horse. 



I have now to show that in the domesticated horse this type of the 

 skeleton is sometimes widely departed from. To begin with, the limbs fall 

 inwards under the body, the elbows and stifles being then closer together 

 than the shoulder and hip joints (fig. 3 c). In addition, the bones of the 

 limbs subside in a spiral manner, so as to turn the joints outwards in an 

 increasing degree as far down as the knees and hocks. If this were 

 continued, the feet would be turned entirely outwards. There is, however, a 

 rectifying twist in the bones below the knees and hocks, which partially 

 restores the forward direction of the limbs (fig. 4, next page). It need hardly 

 be mentioned tliat in the horse showing this condition of the limbs, the 

 alteration of the bone is not confined to the limbs. The subsidence of bone 

 is found also in the rest of tlie bones of the skeleton, which together form the 

 two great cavities — the neural cavity and the visceral cavity of the skeleton. 

 Tlie essential organs contained in tliese restricted cavities are on the same 

 inferior scale ; and function consequently is everywhere inferior. 



This deterioration in the skeleton of the horse is easily seen in the living 

 animal. It is noticeable, for example, in the turning inwards of the femur, 

 especially during movement. Viewed from behind, the horse free from 



I am indebted to the courtesy of Dr. Scharif for an examination of these specimens. 



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