332 



MUTATIONS IN EYE-COLOR OF DROSOPHILA. 



In order that the full data may be recorded for this interesting case Miss 

 Moody's records may now be given in detail, where the record of each bottle 

 containing a sin 



pair each is recorded. For convenience these bottles 

 which the F 2 flies contained all four (or three of the four) expected classes are 

 first given (99 bottles in all), and then the records of 32 bottles in which only 

 red flies appeared in the second generation are given. If the latter 32 bottles 

 be excluded the ratio of Reds to Pinks is found to be 4.127 to 1, which is not 

 very different from the results obtained by Mr. Litt. But as I have stated 

 there is no sufficient reason for excluding these 32 cultures. The small number 

 of offspring obtained from certain pairs is significant, and can scarcely be due to 

 sterility. As small bottles or vials were used in these experiments it is not im- 

 probable that all of the offspring were not obtained ; and, as already pointed out, 

 failure to run each bottle to completion (i. e. more than the prescribed ten days 

 after the first flies hatched) would cut down the Pinks disproportionately to the 

 Reds. 



Records of Fj Reds (Moody). 



Bottle. 



I 



II 



III 



IV 



v 



VI 



VII 



VIII 



IX 



X 



XI 



XII 



XIII 



XIV 



XV 



XVI 



XVII 



XVIII 



9 



<J 



31 



27 



38 



33 



40 



21 



41 



31 



22 



15 



7 



6 



11 



9 



25 



19 



18 



12 



25 



33 



3 



7 



22 



27 



35 



25 



3 



7 



20 



14 



31 



12 



12 



8 



18 



16 



13 



13 



14 



12 



13 



12 







Total 



Bottle. 



58 



71 

 61 

 72 

 37 

 13 

 20 

 44 

 30 

 58 

 10 

 49 

 60 

 10 

 34 

 43 

 20 

 34 

 26 

 26 

 25 



XXII 



XXIII 



XXIV 



XXV 



XXVI 



XXVII 



XXVIII 



9 



d 1 



XXXIII 

 XXXIV 



XXXVI 



XXXVII 



XXXVIII 



XL 



XLI 



XLII 



28 

 9 



20 

 32 

 18 

 32 



11 

 9 



15 

 2 



19 



7 



20 



19 



9 



2 



3 

 5 



2 



5 



1 



26 



8 



16 



9 



15 



32 



21 



8 



4 



2 



Total 



54 

 17 

 36 

 41 

 33 

 64 

 32 

 17 

 19 

 4 



710 





The Pink-Orange Ratio. 



In my former paper a peculiar result was recorded in the F 2 generation when 

 pink males were mated to orange females. I stated that I " could offer no reason- 

 able explanation of this peculiar relation." In this cross I found for instance, 

 that while in the F x generation (that gave pink females and orange males) the 

 two sexes were approximately equal in numbers, in the F 2 generation, on the 

 other hand, the following proportions were obtained : Pink 9 572, Pink cf 292, 

 Orange 9 312, Orange & 522. There were twice as many pink females as pink 



males ; but only half as many orange females as orange males 



The result could 



not be attributable here to differences in the viability of the pink and orange 





