36 Varietäten, Descendenz, Hybriden. 



Mendelian recessive to the type. In the wild State it is extremely 

 rare, and is found almost exclusively in the female. 



The author has made the various possible matings between 

 lad. $, gross, g and 5, and heterozygous gross. <$ and $. 



The important points in the resulfs of these matings are (1.) that 

 lacticolor males can be obtained by pairing a lacticolor female with 

 a heterozygous male, in which case lad. J, gross. J, lad. $, and 

 gross. $ are obtained in approximately equal numbers. (2.) The con- 

 verse eross, heterozygous female X lacticolor male gives all the 

 males gross, (heterozygous) and all the females lad. 



The author's explanation, somewhat simplified on a Suggestion 

 offered by Bateson and Punnett, is that (1.) the sex-determinants 

 behave as Mendelian allelomorphs, femaleness being dominant; 

 (2.) female individuals are heterozj^gous in respect of sex, having the 

 Constitution <j></, and producing male-bearing eggs and female-bearing 

 eggs in equal numbers; males are homozygous, of the Constitution 

 <f</\ producing only male-bearing spermatozoa; (3.) that there is 

 repulsion between the determinant for femaleness and the grossula- 

 riata determinant in oogenesis, so that the male-bearing eggs carry 

 the grossulariata and the female-bearing eggs the lacticolor character. 



This explanation is found to be in accordance with all the facts 

 and it now receives important confirmation. "For it now appears 

 that when a wild grossulariata female is paired with a lacticolor 

 male, all the male offspring are grossulariata and all the females 

 lacticolor; i. e. the same result is obtained with wild females, which 

 have never been crossed with the rare lacticolor variety, as is pro- 

 duced by pairing a first cross grossulariata female with a lacti- 

 color male." 



"It may, therefore, be regarded as certain that in the moth 

 Abraxas grossulariata males are normally homozygous in respect of 

 the grossulariata character, but all the females are heterozygotes 

 carrying the recessive lacticolor. The exceptional and very rare pro- 

 duction of a wild lacticolor must be due to some accidental distur- 

 bance of the association of the grossulariata determinant with the 

 male-bearing egg." 



The results of the breeding experiments are given in detail in 

 a series of tables. R. P. Gregory. 



Durham, Fl. M. and Dor. C. E. Marryat, Note on the Inner i- 

 tance of Sex in Canaries. (Rep. Evol. Comm. Roy. Soc. IV, 

 p. 57-60. 1908.) 



The authors find that when the cinnamon canary is mated with 

 other varieties the results obtained are very closely parallel to those 

 described by Doncaster in the case of the moth Abraxas grossu- 

 lariata and its variety lacticolor (see preceding abstract). One point 

 of difference between the two cases occurs, for whereas in the 

 canaries the mating dominant <j> X recessive £ has sometimes given 

 dominant $ s, these were not proved to occur in the corresponding 

 families of grossulariata. With this exception the interpretation sug- 

 gested for the results obtained in the moth can be applied to those 

 in the canaries, and the authors conclude that just as the normal 

 females of the moth Abraxas grossulariata are in reality hybrids in 

 the lacticolor character, so the ordinary black-eyed hen canaries are 

 hybrids in the pink-eyed (cinnamon) character. 



The authors remark that thjugh the general course of the phe- 



