INHERITANCE IN RACE HORSES 87 



for broAYii or bay. That will afford a further oppor- 

 tunity to test the Mendelian interpretation of this 

 case. 



We need not, however, wait for this future 

 mating, because Mr. Huby, the stud groom to the 

 Duke of Portland's stud at Welbeck, tells me that 

 " Pontoon " had a foal previous to " Postumus," by 

 *' Gold," and that it was brown. Now for a gi'ey 

 horse like " Pontoon " to have a brown foal by any 

 kind of mating, shows that it is not a pure grey 

 horse (in Mendelian language is not homozygous 

 for greyness) but is carrying in its sex-cells 

 brownness as well as greyness. The assumption, 

 therefore, which the appearance of " Postumus " 

 out of " Pontoon " by " St. Simon " suggested, that 

 "Pontoon" is a D R, where D stands for dominant 

 greyness and R for a colour recessive to it, such 

 as brown or bay, is thus demonstrably proved by 

 the nature of her raatings and of her resulting 

 offspring. 



" Top Hane," another interesting grey horse, 

 appears to have the same gametic composition as 

 " Pontoon." She is a foal of the grey stallion 

 *'Le Saucy," out of the bay mare, "Distingue." 

 Consequently she will be a D R for greyness, and 

 half of her sex-cells will in that event carry the 

 factors for the grey character, and the other half 

 will carry them for the brown or bay character. 

 Both brown and bay, in addition to gTey offspring, 

 may therefore be expected among her offspring if 

 she is mated with a sire like " St. Simon," wdio is 



