No. 589] SHOBTER ARTICLES AND DISCUSSION 49 



parentage produce nothing but albinos, writes that a pair of 

 albinos produced some brown-and-white, some plum, some grey, 

 and some albinos. If this result occurred under all precautions, 

 it stands alone." Allen ( '04) attempted to account for this case 

 by postulating an error in recording the true sire, or that the 

 animals used were not true albinos but black-eyed whites. That 

 two individuals having white coats and pink eyes can give colored 

 young is perfectly possible. The pink-eyed whites in my cul- 

 tures have a white pelage because of the combined effect of the 

 dominant and recessive spotting, while their pink eye is due to 

 the loss of the dark-eye factor. They still retain the color factor, 

 although they show no color. They may be called albinos, if we 

 define an albino as any pink-eyed white individual; but they 

 should be carefully distinguished from that type of albinism 

 which is due to the loss of the color factor. If we mate these two 

 different types of albinos together, we should obtain colored 

 young. The cross may be expressed in symbols: 



PpssddCC X ppSSDDcc P. zygotes 



PsdC + psdC gametes of pink-eyed white 



pSDc + pSDc gametes of albino 



PpSsDdCc + ppSsDdCc i\ zygotes 



Spotted + Selfs 



It is interesting to note that the exceptional case, quoted by 

 Bateson, mentions the occurrence of spotted and selfs in the 

 cross of two albinos. In plants, as in animals, similar somatic 

 characters do not necessarily indicate similar germinal con- 

 stitution. 



Our assumption of the interaction of a dominant and recessive 

 spotting factor to account for the white pelage of pink-eyed and 

 black-eyed whites is strengthened by the valuable paper of Little 

 ('15). Little has adopted a similar hypothesis for black-eyed 

 whites in his paper just published, and quite different from the 

 hypothesis of his earlier paper. ('13). It should be stated that 

 Little's experiments furnish even a larger amount of data from 

 the more convincing type of matings than has been possible in our 

 own cultures as yet. J- A. Detlefsen. 



REFERENCES 



Allen, G. M. 1904. Proc. Am. Acad. Arts and Sci., vol. 40, pp. 61-163. 

 Bateson, W 1903. Proc. Zool. Soc. London, vol. 2, pp. 71-98. 

 Durham, F. M. 1908. Royal Soc, Rep. Evol. Comm., No. 4, pp. 41-53. 

 Little, C. C. 1913. Carnegie Inst. Wash., Pub. 179, pp. 11-102. 

 Little, C. C. 1915. Am. Nat., vol. 49, pp. 727-740. 



