404 Dr. F. Galtoa. The average Contribution of each 



containing the pedigrees, dates of birth, and the names of the 

 breeders of these valuable animals. The one I have used bears the 

 title ' The Basset Hound Club Rules and Stud-Book,' compiled by 

 Everett Millais, 1874-1896. It contains the names of nearly 1000 

 hounds, to which Sir Everett Millais has very obligingly, at my 

 request, appended their colours so far as they have been registered, 

 which during later years has almost invariably been done. The 

 upshot is that I have had the good fortune to discuss a total of 817 

 hounds of known colour, all descended from parents of known colour. 

 In 567 out of these 817, the colours of all four grandparents were 

 also known. These two sets are summarised in Table I and discussed 

 in Table V, and they afford the data for Tables II, III, and IV. In 

 188 of the above cases the colours of all the eight great-grandparents 

 were known as well ; this third set is discussed in Table VI. 



Partly owing to inequality in the numbers of the tricolours and 

 non-tricolours, and partly owing to a selective mating in favour of 

 the former, the different possible combinations of T. and N. ancestry 

 are by no means equally common. The effect of this is 'conspicuous 

 in Table I, where the entries are huddled together in some parts and 

 absent in others. Still, though the data are not distributed as evenly 

 as could be wished, they will serve our purpose if we are justified in 

 grouping them without regard to sex; or, more generally, if we 

 treat the 2 n components of each several A„, whatever be the value of 

 n, as equally efficient contributors. 



Our first inquiry then must be, "Is or is not one sex so markedly 

 prepotent over the other, in transmitting colour, that a disregard of 

 sex would introduce statistical error ? " In answering this, we should 

 bear in mind a common experience, that statistical questions relating 

 to sex are very difficult to deal with. Large and unknown disturbing 

 causes appear commonly to exist, that make data which are seemingly 

 homogeneous, very heterogeneous in reality. Some of these are un- 

 doubtedly present here, especially such as may be due to individual 

 prepotencies combined with close interbreeding. For although this 

 pedigree stock originated in as many as ninety-three different hounds, 

 presumably more or less distant relations to one p.nother, some of 

 them proved of so much greater value than the rest that very close 

 interbreeding has subsequently been resorted to in numerous in- 

 stances. In order to show the danger of trusting blindly to averages 

 •of sex, even when the numbers are large, I have compared the 

 results derived from different sets of data, namely from those con- 

 tained in the last two columns of Table I, where they are distin- 

 guished by the letters A and B, and have treated them both sepa- 

 rately and together in Table II. They will be seen to disagree 

 widely, concurring only in showing that the dam is prepotent over 

 the sire in transmitting colour. According to the A data, their 



