Xo. 025] SHORTER ARTICLES AND DISCUSSION 



185 



Xo. .-, Cons. Perm. Intern. Expl. Mer. 



A NOTE ON THE FATE OF INDIVIDUALS HOMO- 

 ZYGOUS FOR CERTAIN COLOR FACTORS 

 IN MICE 



TSBEN and Steip:l(Mler have reported on certain ])ree(]iiia' e: 

 periments with mice which produce evidence in supixMi (»f ili 

 view advanced by Castle and the wi'itei- ni jukI lair 



strengthened by Kirkham. 1917, that lioniozy-diis yellow mir 



the results of Isbeii aiul SirinhMlcr aii.l of Kirkham were ob- 

 tained. It seems best at tins tniH- to put these results on record. 



The embryos referred 1o a> • ■ ahnoimar " may be considered 

 as fallinpr in Isben's and Sf cjoliMl.'r "s Class A of dead embryos, 

 that is to say, those in which drvclo|)nicnt ceased shortly after 



suited probably from overcrowdinii' within the uterus during 



Tliree typ. ^ of nialiius ro rontrol the results in yellow X 

 yelh)w ci'iw^cs wciv made. In all eases, the non-yellow animals 

 used were taken from the same stoek as that produeinp: the yel- 

 lows. The control maiinos mad.- were as follows: Yellow female 

 X non-yellow male, non-yellow female ^- yellow nuile and finally 

 non-yellows cross.Ml mhr si . The numbers ol)tained arc small 

 and are grouped together in the following table: 



