OBCHID CONFERENCE. 



417 



CO and EE represent double presence of factors G and E — i.e., 

 homozygous, or pure. 



Co and Er represent single presence of factors C and E — i.e., hetero- 

 zygous, or impure. 



cc and rr represent absence of factors C and E — i.e-., zerozygous, or 

 wanting. 



The same scheme of course applies equally to coloured forms 

 as to albinos. Thus four distinct kinds of coloured forms are possible, 

 viz. : — ■ 



(a) CCEE 



(b) CCEr 



(c) CcEE 



(d) CcEr 



These four coloured forms may be absolutely identical in appearance 

 and outward characters, yet each has a different germinal constitution, 

 and consequently will give different results in breeding. Of the ten 

 possible matings, five will give all coloured forms, four will give on 

 the average three coloured forms to one albino, and one will give on 

 the average nine coloured forms to seven albinos. 



Table II. gives the factorial details of these matings, showing how 

 ' the above calculations have been made. 



Table II. — (Coloured Matings 



Parents 



Offspring 



Eesult 



(a) CORE, X {a) CCRR 

 (a) CCRR X (6) CCRr 

 (a) CCRR X (c) CcRR 

 (a) CCRR X {d) CcRr 



(6) CCRr X (6) CCRr 

 (6) CCRr X (c) CcRR 



j(6) CCRr X {d) CcRr 



[c) CcRR X (c) CcRR 

 'c) CcRR X (d) CcRr 



d) CcRr X {d) CcRr 



All CCRR 

 1 CCRR : 

 1 CCRR : 

 1 CCRR : 

 1 CcRr 

 1 CCRR : 

 1 CCRR : 



1 CcRr 

 1 CCRR : 



2 CcRr ; 

 1 CCRR : 

 1 CCRR : 



2 CcRr 

 1 CCRR : 

 2 CCRr 

 1 CCrr : 



1 CCRr 

 1 CcRR 



1 CCRr : 



2 CCRr : 

 1 CCRr : 



1 CcRR : 

 : 1 CCrr : 



2 CcRR 



1 CCRr : 

 : 1 ccRR 



2 CcRR : 

 : 4 CcRr 

 2 Ccrr : 



1 CcRR : 



1 CCrr 



1 CcRR : 



2 CCRr : 

 : 1 Ccrr 



: 1 ccRR 

 2 CcRR ; 

 : 1 ccRr 

 1 ccRR ; 

 : 2 ccRr 

 1 ccrr 



All Coloured 

 All Coloured 

 All Coloured 

 All Coloured 



3 Coloured : 1 Albino 

 All Coloured 



6 Coloured : 2 Albinos 



3 Coloured : 1 Albino 

 6 Coloured : 2 Albinos 



9 Coloured : 7 Albinos 



by 



mating 



the four 



Further interesting results will be obtained 

 ioloured forms with the five albinO' forms. 



Of the twenty possible matings, seven will give all coloured forms, 

 iight will give on the average equal numbers of coloured and albino 

 brms, tw^o will give three coloured forms to five albinos, two will give 

 hree coloured forms to one albino, and one will give one coloured 

 orm to three albinos. 



Table III. gives the factorial details of these matings, showing how 

 he above calculations have been made. 



VOL. XXXVIII. E E 



