398 Note on the Offspring of Thoroughbred Chestnut Mares. 



sires into groups, those of each group giving a definite proportion of Chestnut 

 foals when mated with Chestnut mares. My observations do not at present 

 decide this point ; but through the period I have dealt with no such separation 

 of sires into groups seems possible. Taking only the Bay or Brown sires 

 which have given at least 20 foals in the period covered by my records, I find — 





Foals. 



Sire. 









Ch. 



Not. 





1 



42 





1 



28 



Minting 



2 



31 





2 



29 



at one end of the series and at the other such sires as Bightaway 

 (21 Ch. + 10 Not), or Queen's Birthday (13 Ch. + 3 Not), which offer a 

 transition to such Chestnut sires as Amalfi. 



The detailed discussion of individual sires, and of the proportion of Chest- 

 nuts yielded by each, must be postponed until the work of extracting the 

 records from the Stud-Book lias been completed. In the meantime, however, 

 the following points seem clear : — 



1. No simple Mendelian view of the relation between Chestnut, Bay, and 

 Brown, regarding Chestnut as a simple recessive, can be maintained. 



2. The chance of getting a Chestnut foal from a Chestnut mare is not con- 

 stant for sires of any colour whatever, and there is no indication that sires of 

 any colour can be sorted into groups such that those in each group will 

 give Chestnut foals in a Mendelian proportion when mated with Chestnut 

 mares. 



3. These points, together with the values for parental and grand-parental 

 correlations already given by Professor Pearson* make it probable that the 

 facts of inheritance of coat colour in horses can be expressed in terms of the 

 hypothesis outlined by Mr. Galton in 1872,f and developed by him in his 

 subsequent writings. 



I hope to discuss the application of Mr. Galton's hypothesis to these data 

 before long ; but the extraction of pedigrees from the Stud-Book is an opera- 

 tion which takes time, and I have felt bound to offer this imperfect statement 

 in justification of what I said in the discussion to which I have referred, 

 without waiting until my work should be completed. 



* ' Phil. Trans.,' A, vol. 195. 



t ' Eoy. Soc. Proc.,' No. 136, pp. 394—402. 



