196 ANIMAL PEDIGREES 



many other contemporary ancestors from any of 

 whom our path might with equal truth have com- 

 menced. 



A man has two parents, four grandparents, eight 

 great-grandparents i.e., in tracing back his pedi- 

 gree from the present time the number of his 

 ancestors in each generation is double those of 

 the generation that succeeded it in time. This 

 is graphically expressed in the following diagram : 



M. 



l\/\ l(\ l(\ /A 7 s 



Parents. 

 Grandparents. 



Great-grand- 

 ents. 



great- 

 DlAGRAM C. grandparents. 



which takes, as noted above, the form of an inverted, 

 not an erect, tree. If we allow three generations 

 to a century there will have been twenty-five 

 generations between the Norman Invasion and the 

 present time : so that a man now living may 

 be descended not merely from one ancestor who 

 came over to England in 1066, but directly and 

 equally from over sixteen million ancestors who 

 lived at or about that date. I say advisedly " may 

 be descended;" for unless we assume that many of 

 these ancestors were identical individuals, we shall 



