Xl GENERAL INTRODUCTION. 



Before leaving the subject of reversion I may refer to 

 a hinny (jennet) recently added to my stud. This young 

 hinny (a cross between a bay Welsh pony stallion and a 

 common ass) is of a yellowish-brown colour — the colour 

 of the wild horse of the Dzungaria Desert — and has 

 distinct bars at the '^ knees " and hocks, as well as a 

 dorsal band and a shoulder stripe. The leg bars are 

 evidently due to reversion, as no leg bars are present in 

 either of the parents. Reversion of this kind is very 

 common in mules, and is not unknown amongst pure-bred 

 asses and zebras. A zebra foul, e.g., born during the 

 present summer in the Eegent's Park gardens, London, 

 is striped to the hoofs, and is in other respects like the 

 zebra named after Mr. Selous. In the parents, which 

 belong to the Chapman variety, the legs are only partially 

 striped. Several of my hybrids have more bars on their 

 legs than their sire. 



From what has been said as to reversion, it is evident 

 that breeders should in all cases direct as much if not 

 more attention to the ancestors than to the parents of 

 their breeding stock, that they should expect and make 

 allowance for reversion, for " regression towards medio- 

 crity,""^ especially remembering that the more unlike the 

 parents the greater is likely to be the reversion in the 

 offspi'ing, and that the hitest acquired peculiarities are 

 likely to go first unless they have been " fixed " by 

 inbreeding, or are of the nature of " sports." 



As indicated in the last of the three papers, it has 

 been the fashion for some time to throw doubt on the 

 reversion hypothesis. It has been stated that " around 

 the term reversion a singular set of false ideas have 

 gathered themselves.'' t But statements of this kind 

 do not disprove reversion. Even if the hypothesis in 

 question has been invoked to account for the appearance 



* Evidently the more inbred and closely related the parents the more 

 limited will be the rancre of reversion, but still even in grossly inbred stock 

 reversion will occasionally occur, especially to prepotent and not very far 

 removed ancestors. 



t Bateson, 'Materials for the Study of Variation,' p. 7^. 



