102 



PROCEEDINGS OP THE AMERICAN ACADEMY. 



represent in some cases a number of litters from various parents. These 

 three tables may now be examined with a view to observing whether or 

 not complete albinism is pi'esent in one in sixteen of the offspring, as is 

 expected. 



By way of explanation it may be stated that Crampe used abbrevia- 

 tions for denoting the colors of his rats. Thus, in the tables which follow, 

 " var. 5 " denotes a black-white rat, " var. 6 " is a black animal with 

 small flecks of white, usually confined to the feet, forehead, middle of 

 belly, and tip of tail, and " var. 7 " is wholly black. 



TABLE M. 



(Based on observations of Crampe.) 



