130 THE EXTERIOR OF THE HORSE. 



ment. An apparent narrowness of the croup, due to this cause, may 

 exist, all things being otherwise normal, so marked as to diminish the 

 transverse diameter of the croup by more than six centimetres. 



As to the degree of concavity of the external face of the ilium, its 

 influence is easily understood. It augments thereby the surface des- 

 tined for muscular insertion. Let us confine ourselves by saying that 

 it is often much more pronounced than can be determined from the 

 exterior. 



The practical conclusion to be drawn from these statements is 

 simple : to judge well the width of the croup, it will suffice to consider 

 the transverse dimension of the cavity of the pelvis. With equal 

 length of the ilium, preference is to be given to the horse in which the 

 sides of this region are inclined, — that is to say, a great diiference of 

 level between the haunch and the summit of the croup is desirable, 

 the separation of the haunches remaining the same. 



Two objectionable consequences may result from excessive width 

 of the croup and a too marked inclination of its sides. Too widely 

 separated from the median line, the coxo-femoral articulations require too 

 large a base of support, and consequently produce exaggerated lateral 

 oscillations of the posterior part of the body during locomotion. From 

 this results an ungraceful swaying of the buttocks, which has been 

 called the rocking of the horse ; whence results a loss of force and time 

 proportional to the extent of these movements and the excessive oscil- 

 lations of the centre of gravity. The conditions of locomotion require 

 the centre of gravity to move in as straight a line as possible, because 

 force is required to displace it from that line. In draught-horses this 

 defect is of no importance ; in animals used for other purposes it is detri- 

 mental, and a mean obliquity of the sides of the croup is preferable. 



Other defects, not less serious, may result from an excessive inclina- 

 tion of the lateral parietes of the croup, as is seen more particularly in 

 the form in which it is designated sharp. Here the base of support 

 is narrow and the hind limbs do not have their necessary freedom of 

 movement during rapid locomotion ; they approach each other, the 

 abduction is limited, and the animal will interfere or forge. Let us 

 add that such a croup lacks strength and beauty, and is often accompa- 

 nied by a narrow chest, sufficient cause to render the animal unfit for 

 for some kinds of work. 



The absolute narroioness of this region is at all times regarded as a 



defect. 



Direction. — The direction of the croup has been the theme of 

 extensive discussions among authors who have written upon the exte- 



