ALLEN. — THE HEREDITY OF COAT COLOR IN MICE. 



89 



wild, a pied, and an albino, were interbred, whereas in other cases only 

 two of these stocks were kept together. After a long study of Crampe's 

 tables, the writer has been able to extract from them a number of cases 

 in wliich it is evident that both parents concerned w.ere pied or mosaic 

 animals having the albino character recessive, as evidenced by the pres- 

 ence of albinos among their young. Crampe seems to have kept some of 

 his rats together in '* families," by which term he refers to certain lots. 

 Others seem to have been single pairs. The following Table (I) shows iu 

 condensed form the results of these crosses. Other crosses, by which 

 albinos were produced, are considered under a separate head, as tlie 

 families appear to have had three characters among them, instead of the 



two here treated. 



TABLE L 



In these crosses, it is plain that the numbers of young given for the 

 respective pairs represent in some cases the totals of successive litters, 

 while in others they indicate single litters. In each case, however, the 

 theoretical number of albinos is very nearly realized, and although there 



