HEREDITY OF RACEHORSE STAMINA 71 



inhibitory factor would ex hypothesi reduce them to 

 sprinters. As, approximately, only half of the PR 

 stallions' gametes carried R, their percentage of 

 staying produce must fall considerably below that 

 of RR stallions in the same mating. The actual 

 result shows that the crossing of the seventeen RR 

 sires with PP and (PR +1) mares gives 48*0 per cent, 

 of stayers (see Table VIII.), whereas the heterozy- 

 gous PR stallions show 15 per cent, of stayers from 

 the same mating. (See Table X.) 



In the next mating, PR sires to PR mares, the 

 result is remarkably close to the typical ratio of 

 1:2: 1, and affords unmistakable evidence of 

 Mendelian segregation. The expectation is 48 : 96 : 

 48. The result is 44 : 88 : 60. 



The three sprinters from the mating of PR sires 

 with RR mares, just considered, are aberrant. One 

 of these was the gelding Ashdod, who, like certain 

 other sons of Gallinule, broke blood vessels. Another 

 is Mailed Fist, by Orme out of Gantlet. This mare 

 Gantlet won the Park Hill Stakes, Doncaster, nearly 

 fifteen furlongs, but the fillies she beat were, like 

 herself, non-stayers. Next year, as a four-year-old, 

 she ran at five and eight furlongs. She is the dam of 

 Duke of Westminster, also by Onne, and of Grey Plume, 

 by Grey Leg, neither of which could stay more than 

 a mile. The third sprinter from PR xRR is Excelsior, 

 by Eager out of Perchance (by Persimmon). Per- 

 chance won one race only, and is probably an inter- 

 mediate. 



In the last series of matings shown in Table X., 



