92 
PROFESSOR K. PEARSON AND DR. A. LEE ON 
from the above, and possibly filling up the numerical gap between them. To this 
point I shall return when dealing with the observed values for eye-colour in man. 
Part IT.— Ox Colour-Inheritance in Thoroltghbred Racehorses. 
(6.) All the data were extracted from Weatherby’s stud-books, the colours being 
those of the horses as yearlings. My first 
tive scale, of horse-colours. With this 
examined, and, including the arabs, the 
found :— 
1 . Black (bl.). 
2 . Black or brown (bl./br.). 
3. Brown or black (br./bl.). 
4. Brown (br.). 
5. Brown or bay (br./b.). 
6 . Bay or brown (b./br.). 
7. Bay (b.). 
8 . Bay or chestnut (b./ch.). 
9. Chestnut or bay (ch./b.). 
step was to form an order, not a quantita- 
end in view, the recorded colours were 
following seventeen colours were at first 
10. Chestnut (ch.). 
11. Chestnut or roan (ch./ro.). 
12. Roan or chestnut (ro./ch.). 
13. Roan (ro.). 
14. Roan or grey (ro./g.). 
15. Grey or roan (g./ro.). 
16. Grey (g.). 
17. White (w.). 
Now, if we take the alternative colours to mean that the first alternative is the 
prominent element, we see that these colours in use among breeders admit of only one 
arrangement from black to white. That is to say, that a continuous shade-change is 
actually in use for the colour-nomenclature of thoroughbred horses. # Thus without 
any hypothesis as to the quantitative relative values of bay or roan, we have an order 
which serves for all our present purposes. Following this order, Appendix I., Tables 
I.—XII., for the colour correlation of related pairs of horses was compiled by 
Mr. Leslie Bramley-Moore from the stud-books. When dealing with relationship 
m the ? line only, no weight has been given to fertility, as each mare has had only 
one foal attributed to it, or two in the case of fraternal correlation. In the case 
of the d line, the colours of the older sires were harder to ascertain, and we did not 
obtain altogether more than 600 sire-colours. Thus one, two, or, in a few cases, three 
or four colts or fillies were taken from each sire. 
I shall now discuss the results which may be drawn from these tables for the theory 
of heredity, first placing in a single table all the numerical constants calculated from 
the data in Tables I. to XII. of Appendix I. 
* Among the 6000-S000 horses dealt with only four were found with colours not entered in this scale, 
but these entries of bl./ch,, br./ch., b./ro., in no way contradict the order of the scale, but merely show a 
rougher appreciation on the part of the nomenclator, or possibly printers’ or editor’s errors. 
