XO. C39] INIIERITAXCE OF BLl'K IN POULTRY 309 



havp Wn- honmzvuous tor a .Inniina,.! wlilf factor. 

 AVlu'tlier it can-ird /' .)r tlir c-vidcR-c .l.u's not >liow. 



So far no attempt has hem made to ascertain wli.'thcr 

 this factor for doiiiiiiaiit white is the same a> that nor- 

 mally carried by the white Leghorn and wliich llacUey 

 (1913 and 1914) designated as /. For convenience and 

 to recognize the possibility of its ditfering from / the 

 factor here dealt with is referred to in this paper as 

 (inhibitor of pigment) and its allelomorph as i''. 



VII. Back-ceosses of Fj 's fkom Blue-splashed 

 ANDALrsL\N X Recessive White Matixgs 

 The results of crossing the Fj blues from the blue- 

 splashed Andalusian X recessive white crosses is sho-wii 

 in Table III. 



While by no means all possible back-crosses have been 

 made, enough are represented to sliow clearly that factors 



and £' were appearing' in appro .\iniatel\- eoual nnml)ers, 

 and that this was also trn.' of P an.l thou-h in <ome 

 cases the presence of coniplica1e<l matto's sonn*\vhat. 

 It was, unfortunately. n..t always ])..^sil.le t.. use the 

 actual paivnts in niakin- l^ack-ci-osses and tliouuh indi- 



proved to be no eriterion that tiu^v uviuld he'of'the same 

 genotype as the indixidnals used in the oriuinal crt^ss. 

 There can be no <|ue>tion as t.. their lactorial comi-osi- 

 tion, however, as •■ach individual has been eithei- delib- 

 erately tested or had happeiu'd to be so mated for another 

 purpose as to give dependal)le ex'iih'nce on its composi- 

 tion with respect to and p. 



So far as it goes, the evi<lem-e, which is sal>stan! iated 

 by the results of other crosses to be re])orted in a later 

 section of this pa])er, al>o -hows that the meetinu' of P 

 and R was accordinu- to chance. tliereb\- indicatinu- no 

 linkaire between these two fact<.rs. 



It will be noted that the bhn' F, : ? in -nu, p o of Tal^N 

 111 had a hlue Andalusian mollier instead of a i^u. 



