K. Pkaiison Axi) A. Lkk ;5!)1 



I hiive aol placed in tliis table tlio rcsults für stature as fouiid fnMii Air 



Galton 's Family Data, iior those for Copluilic Iiulox for North Aniorifau IiKlians, 



because I considiT lliat tlie rcsuKs f'nr Kolli ihcsc charaetcrs are replaced by tlic 



largor series we liavc iiow at oiir disposal, and which are iucluded uniler " man " 



in the above iist. Otherwise it cmbraces iiearly all the data wo have as yet 



at oiir (lisposal. Now it is clear tliat the valne for man is aboiif, •") and agrees 



well with t,he value found for Hasset llunnds, aiid iiideed with that for tlie Sliii'ley 



Poppy, assiimin<,' eoniplete cross fertilisation*. On the other band the horsus aud 



greyhoniids, while agreeing xuell with man für the pdrental correlations (see Table 



V. p. -23), show a nmeh increased fraternal correlation of the same order as that 



betwocn the parthenogenetic oti'spring of Daphnia and Aphisf. Now how far is 



this due to such factors as unit prepotency or intcrniittent prepotency / All we 



can do at present is to suspend our judgment on this point. In the t-ase of dogs, 



intermittent prepotency might manifest itself by the offspring of the same paronts 



for the same litter being more alike tlian for different litters. Now will this 



account for the high vaines of the greyhound results '. Unfortunately our records 



contain otily greyhounds of the same litter, all menibers being recorded, while the 



volumes of the greyhound stud-book contain only a selection of all dogs born, 



colour undoubtedly being a selected character. Furtlier it is very difihcult from 



those volumes to extract a sufficient number of brethren of füll blood from 



different litters. Still we ho])e to be able to throw some light on the problem of 



at least intermittent prepotency in the case of greyhounds. It is remarkable that 



the fraternal correlation in the Basset Hounds, while according closely with that in 



man, is the same sensibly in intensity for siblings from the same and from different 



litters. The case of the thoroughbred horses is somewhat different, but here we 



propose to draw up separate tables for twin foals and foals from the same parents 



in different years, and thus if possible differentiate intermittent prepotency, if it 



really exists. The high values, however, found for half-siblings in the case of the 



thoroughbreds seeni to indicate that we niust look rather to nnit prepotency than 



intei'mittent prepotency for the source of the high valiic of fraternal as compared 



with parental correlation in the case of the horse. 



What is (juite clear is that we badly want the measurement of further 

 characters for siblings in botli maniinals and insects. The present results show 

 that while the value ".) has overwhelming evidence for it in the case of both 

 measurable aud unmeasurable characters in man, we are yet without like data 

 for the measurable characters in horse, dog or any other niammal. Should these 

 ultimately be found to agree with the results given above for the quantitatively 

 unmeasurable characters, I personally hold at present, that the Solution for equal 

 parental and unequal fraternal correlations in these different species should first be 

 sought in a fidler study of unit and intermittent prepotency. 



* Blometriha, Vol. ii. p. 81. 



+ lu the case of these insects differential enviroiiment may, of coiirsc, have emphasised the 

 resemblance. 



50—2 



