130 



MR. L. DONCASTER AND REV. G. H. RAYXOR OX [Feb. 20, 



It was now shown that the recessive vai-iety hitherto known in 

 the female only could be transferred to the male l)y pairing a 

 heterozygous male with a recessive female. It remained to pair 

 male and female of the variety together, and to pair the recessive 

 male with the heterozygous female. Both these pairings were 

 effected in 1904 and repeated in 1905. 



Lacticolor $ X J (Table XI.) have given exclusively lacticolor 

 oifspring, male and female ; the recessive character breeds true, 

 as was expected. 



Lacticolor rj x heterozygous § (Table X.) have given all the 

 males normal, all the females lacticolor; a result which may have 

 important bea,i-ing on the theory of the determination of sex. 



To sum up — 



DR 2 X DR c? gives DD d , DR J , DR 2 , RR $ . 

 R $ X DR d „ DR c? , RR J , DR 2 , RR 2 . 



DR2 xRcJ 

 R2 xRj 



DRc? 



Rd 



R2. 



Table YIII. — Hetei-ozygous 2 X heterozvgous S 

 (TypeDRxDR.) 



No. of Exp. 



gross. $. 



gross. $ . 



lact. S . 



laet. ? . 



Total. 



03.xii. ... 



25 



14 





9 



48 



03. xxi. ... 



22 



9 





11 



42 



04. X. ... 



13 



1 





15 



29 



L.D. 04. ii. ... 



7 



1 





4 



12 



Total... 



67 



25 





39 



131 



Table IX. — Lacticolor 2 X heterozygous S . 

 (Type R 2 X DR c? .) 



No. of Exp. 



gross. S- 



gross. $ . 



lact. c? . 



: lact. ? . 



Total. 



03. iv. ... 







3 





3 



03. viii. ... 



10 



4 



6 



2 



22 



04. V. ... 



18 



6 



11 





36 



Total... 



28 



10 



20 



3 



61 



