292 Shull. 



These formulae have been used by MORGAN (1911 a), SHULL (1911), 

 STUBTEVANT (1912 a), and GOLDSCHMIDT (1913). 

 Synonymous formulae: 



(1) FFmm = 9, Ffmm = cT (Morgan 1911a, Stevens 1911a). 



(2) MMFF= 9, MMFf= e? (Goldschmidt 1911, 1913, Lang 



1912, Correns and Goldschmidt 

 1913). 



(3) MMFF= 9, MMF = 3 (Morgan 1911 c). 



(4) FF = 9, FO = c? (Morgan 1911 a). 



(5) FF = 9, .FF 1 ) = G? (Spillman 1911). 



(6) XX = 9, X =3 (Wilson 1909, 1910, Castle 1909, 



Morgan 1910a,b, 1911c, 1912a,b, 

 1913c, Pinney 1911, Morgan 

 and Lynch 1912, Dexter 1912, 

 Morgan and Cattell 1912, 1913, 

 Sturtevant 1913). 



(7) MMXX= 9, MMX = <? (Morgan 1911 c). 



(8) XX = 9, X - = cf (Castle 1912, Little 1912, 



Morgan 1911b, 1912c, Bridges 

 1913b). 



(9) XX = 9, XO =<? (Morgan 1911 a, 1913 c). 



(10) xx = 9, xO = c? (Hertwig 1912). 



(11) XX = 9, Xx = cT (Arkell 1912, Arkell and Daven- 



port 1912, Doncaster 1913b). 



(12) XX = 9, XY 1 ) = 3 (Wilson 1909, 1910, Stevens 



1911b, Edwards 1911). 



(13) xx = 9, xtj 1 ) = c? (Hertwig 1912, Schleip 1912). 



(14) 99 = 9, 9 = cT (Shull 1910). 



2. The female is assumed to be a negative homozygote. 

 Model formulae: XXmm = 9, XXMm = <?, 



or simply, mm = 9, Mm cT. 

 These formulae have been used by GOLDSCHMIDT (1913) and Jo- 



HANNSEN (1913). 



*) Formulae (5)y2) and/]|3) have the same construction as those included below 

 under the case in which the female is assumed to he a neutral homozygote. They are 

 included in the present case because the Y or y has been generally represented as a 

 sexually indifferent element. The authors who have used these formulae have not always 

 expressly stated this point, however, so there may be some doubt in such a case whether 

 they should be included here or below under 3. 



