No. 501] 



NOTES AND LITERATURE 



613 



Langshan becomes FB X bb = Fb -fBb, or black (non-barred) 

 females and barred males, as in J. F. Spilman's experiment. It 

 may be plainer to some if we write the above Fb — Bf X f b — 

 fb = Fb — fb + fB — fb. 



Here F is correlated with b, and f with B ; that is, in terms 

 of the chromosome theory, the chromosome which carries F does 

 not carry B, and vice v< rsa, though those two chromosomes unite 

 in synapsis to form a bivalent chromosome. 



The origin of black females from barred parents is, under our 

 theory, the result of mating a barred female with a hotorozygote 

 male ; thus : FB X Bb = FB + Fb + BB + Bb. 



This mating gives half of the females black, the other half and 

 all the males being barred. 



But if we mate a homozygote male barred bird with a non- 

 barred female (carrying black color of course), we get BB X 

 Fb = FB + Bb, both sexes being barred. 



The result of this last mating has not yet been demonstrated. 

 The same is true of the next mating, between a heterozygote 

 barred male and a non-barred female, which should give 

 Bb X Fb = FB + Bb + Fb + bb; that is, half of each sex 

 black. 



Some similar relation undoubtedly exists between a color ele- 

 ment and the sex element both in geese and in ducks, for there 

 are certain breeds of geese in which the males are all white and 

 the females all colored; while in ducks certain breed crosses give 

 the males all of one color and the females all of another. 



Two very interesting cases of allelomorphism between two 

 physiologically unrelated characters are found in the recently 

 published work of Noorduijn on "Inheritance in Canary Birds." 8 

 The data given are not quite full enough to permit their complete 

 elucidation, but they indicate clearly a pairing of the sex ele- 

 ment (female) with yellow coat color, and also with a factor of 

 the compound (from the Mendel ian standpoint) eye color. 

 There are three principal colors in canaries, namely, yellow, cin- 

 namon (brown), and green. Since mating yellow and cinnamon 

 always gives green birds (usually variegated, but part of the 

 body green) we may infer that the green color arises from the 

 combination of yellow and cinnamon, or of characters correlated 

 with these. Noorduijn states that there are three pigments in 

 the feathers of green canaries, namely, yellow, brown and black. 



•C. L. W. Noorduijn, in Arch. f. Fass-. u. Gesdl.-Biol., April, 1908. 

 p. 162 et seq. 



