No. 594] 



COLOR MUTATIONS IN MICE 



349 



exactly the opposite direction from that in which the 

 selection was being made. 



6. A recessive pink-eyed mutation has occurred in a 

 closely inbred dilute brown race. A similar mutation 

 has appeared in a hybrid race into which one animal from 

 the dilute brown race probably introduced the mutation. 



7. A mutation involving loss or suppression of the 

 black producing factor has arisen in a stock of inbred 

 wild mice. This has caused the appearance of brown 

 agouti young. 



8. The wild race in which this occurred is related to the 

 hybrid race (see conclusion 2) in which the white-bellied 

 agouti mutation appeared three times. The suggestion 

 is offered that a tendency to germinal instability may 

 have been transmitted by male 131 a common ancestor of 

 both races. 



LITERATURE 

 Castle, W. E., and Little, C. C. 



1909. Science, N. S., Vol. 30, pp. 313-14. 

 Castle, W. E., and Phillips, J. C. 



1914. Publ. Carnegie Inst, of Wash., No. 195. 

 Cuenot, L. 



1907. Arch, de Zool. Exp. et Gen., Notes et revue (4), Vol. 5, page 1. 



1908. Arch, de Zool. Exp. et Gen., Notes et revue (4), Vol. 6, pp. 

 7-15. 



1911. Arch, de Zool. Exp. et Gen., Notes et revue (4), Vol. 8, pp. 

 40-61. 

 Durham, P. M. 



1911. Journal of Genetics, Vol. 1, pp. 159-178. 

 Little, C. C. 



1913. Publ. Carnegie Inst, of Wash., No. 179. 

 Morgan, T. H. 



1908. Science, N. S., Vol. 27, p. 493. 



1909. Am. Nat., Vol. 43, pp. 182-85. 



1911. Annals, X. Y. Acad, of Set, Vol. 21, pp. 87-117. 



1914. Am. Nat., Vol. 48, pp. 449-458. 



