HEREDITY OF RACEHORSE STAMINA 63 



Offspring of RE, Sires Mated to Random 

 Selection of Mares. 



When we consider the nature of the expected off- 

 spring from RR sires mated with random samples of 

 mares, several interesting points present themselves 

 for consideration. We should, for instance, expect 

 the offspring to consist of stayers and intermediates, 

 but no sprinters. There are, however, one hundred 

 and four of the last group. The stallions numbered 

 1-17 in Table HI. may be taken as RR composition. 

 Diamond Jubilee and Bay Ronald are possible excep- 

 tions, because their produce are rather too few to 

 enable us to form a reliable estimate. The offspring 

 of these seventeen stallions is as follows : — 



Sprinters. 



Colts 61 



Fillies 43 



104 310 396 



Dealing now with the appearance of the one 

 hundred and four unexpected sprinters, we have no 

 difficulty, so far as the 43 fillies are concerned. Three 

 of them won at seven furlongs, the arbitrary upper 

 limit which is fixed for sprinters, and were placed at 

 a mile or over in good company. Their proper posi- 

 tion virtually is in the intermediate group. In regard 

 to the remaining forty, it is highly probable, from the 

 evidence I have already submitted, that all mares 

 sired by RR horses, which do not themselves manifest 

 the R factor, either as intermediates or as stayers, 

 carry a factor for inhibition ; that is to say, these 



