292 Shull. 



Tliese formulae have been used by Morgajst (1911a), Shull (1911), 

 Stuetevant (1912 a), and Goldschmidt (1913). 

 Synonymous formulae: 



(1) FFmm = ?, Ffmm = cf (Morgan 1911a, Stevens 1911a). 



(2) MMFF= 9, MMFf= d" (Goldschmidt 1911, 1913, Lang 



1912, Correns and Goldschmidt 

 1913). 



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

 (^) FF =9, FO = cf (Morgan 1911a). 



(5) FF = 9, -Fi'i) = cf (Spillman 1911). 



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



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

 1913e, Pinney 19U, Morgan 

 and Lynch 1912, Dexter 1912, 

 Morgan and Cattell 1912, 1913, 

 Sturtevant 1913). 



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



(8) XX = 9, Z — = c? (Castle 1912, Little 1912, 



Morgan 1911b, 1912c, Bridges 

 1913b). 



(9) XX = 9, ZO = d (Morgan 1911a, 1913c). 



(10) XX =9, xO = d (Hertwig 1912). 



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



port 1912, Doncaster 1913b). 



(12) XX = 9, Zri) = d (Wilson 1909, 1910, Stevens 



1911b, Edwards 1911). 



(13) XX = 9, xy^) = d (Hertwig 1912, Schleip 1912). 



(14) 9 9 =9,9 = c^ (Shull 1910). 



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

 Model formulae: XXmm — 9, XXMm, = d, 

 or simply, mm = 9 , Mm = d. 

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

 HANNSEN (1913). 



') Formulae (5) (2) and (3) have the same construction as those included below 

 nnder the case in which the female is assumed to be a neutral homozygote. They are 

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

 sexuall}- 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. 



