390 



On (he Lmvx of I nlicritanre in Man 



may in ccrtain imlividiial offspriiig of one and the samc niating, be iJivpntont. 

 ün another occasion, or in oiIkt ortspring of one and the saine niating, it may not 

 be prepotent or even tlie other parent niaj- be prepotent. Such prepotency niight 

 exhibit itself in "alternative" or "exclusive" inheritance*, and is distinct froni 

 any iinit prepotency or absolute or partial domiuance. It does not depend on the 

 possession by one mate of certain characters, but on the condition of the parents 

 and othcr circuinstances peciiliar to a special niating. 



Now the fundamental point to be borne in mind is this, that apart from 

 sex-prcpotency, neither unit pre])i)tency nor intermittent prepotency neetl in any 

 way influence the pareiitai correlations. The avcrage resemblances of ott'spring 

 to either parent will not be attected if in some matings the mother, in other the 

 father is prepotent. Nor again will it be affected, if occasionally the two parents 

 are intermittently prepotent. But such types of prepotency will largely influence 

 the degree of resemblance between brethrcn. If, either invariably or intermittently, 

 one parent is prepotent, the offspring of all matings of these parents or the 

 offspring of one litter will be raore alike, than the offspring of another species in 

 which such prepotency does not exist. When therefore we find parental corre- 

 lation the same for a niimbcr of .specie.s and fraternal corrclation different, I am 

 strongly of opiniou that this will be found to be due to differing amouiits of unit 

 prepotency or of intermittent prepotency or of both combined in diverse species. 

 I have already insisted on this cffect of prepotency in disturbing fraternal corre- 

 lationf, but it seemed necessary again to refer to it as the probable explanation 

 of the great differences observable in the fraternal correlations given below in 

 Table XI. 



TABLE XI. Fraternal Gorrelation in Different Species. 



• R. S. Proc. Vol. Gl), p. 141, etc. and Phil. Tränt. Vol. 19.5, A, p. 89 tt ueq. 

 \ It. S. Proc. Vol. CG, p. 152, and Pliil. Tran.'!. Vol. 19-5, A, p. 101. 



t Unpublished results, tabled by Miss A. Barrington froni Mr Howard CoUins' data, reduced by 

 Dr A. Lee. 



