330 Scientific Proceedings, Roi/al Dublin Society. 



thoroughbred will be understood. To select a sire from any other race but 

 one in which this character is fixed seems to me a very doubtful experiment. 

 Even the harness-horse is the better for being a balance-horse, since otherwise 

 he carries his own weight at a disadvantage. Above every otlier character 

 this is one of most importance in the troop-liorse. Tlie figure above quoted 

 shows very plainly the short thigh and the open angle of the stifle. It 

 will be evident that the English tlioroughbred has not inherited tliis 

 character from his Arab ancestors. It is an historical fact that the Arabs 

 imported into England were themselves slow, whereas their immediate 

 progeny were fast. The inference is that the English mares had this 

 character. It is, however, not absolutely invariable in the English thorough- 

 bred. It is apparently a dominant character. 



Plate XX., fig. 2, shows a typical trooper supplied from Canada to 

 South Africa for the war, sliowing the long spine and the vertical curvatures, 

 also the defect of the fore limb. In it, however, there is the character of the 

 straight hind leg. Such a race as this, influenced by the Arab, would 

 probably lose the defects of both sides. 



Plate XX., fig. 3, represents a typical Australian horse, showing the 

 short fore and hind limbs and the defect of the long spine with the marked 

 vertical curvatures. 



Might not the primitive character of the short spine and skeleton, as 

 opposed to deterioration from this type, be Mendelian dominant features ? 



It appears to me also that the latest phases in the evolutionary shortening 

 of the arm and thigh probably descend in the same way. Whether this is so, 

 and whether also the descent of these characters is limited by sex influence, 

 only the test of breeding can determine. 



I desire, before concluding this paper, to acknowledge my great 

 indebtedness to Dr. Scharff, of the National Museum, Dublin, for tlie 

 help he has given me in its preparation. 



