50 The Dancing Mouse 



mice a very comical appearance. The animals of the second 

 group resembled more closely in appearance the common 

 albino mouse. They possessed the same pointed snout and 

 long body, and only the presence of black spots on the head 

 and hips rendered them visibly different from the albino 

 mouse. 



In behavior the individuals of these two groups differed 

 strikingly. Those of the first group danced frequently, 

 violently, and in a variety of ways ; they seldom climbed on 

 a vertical surface and when forced to move on an incline they 

 usually descended by sliding down backwards or sidewise 

 instead of turning around and coming down head first; 

 they gave no signs whatever of hearing sounds. Those of 

 the second group, on the contrary, danced very moderately 

 and in few ways; they climbed the vertical walls of their 

 cage readily and willingly, and when descending from a 

 height they usually turned around and came down head first ; 

 two of the four evidently heard certain sounds very well. 

 No wonder that Cyon suggests the possibility of a different 

 origin ! It seems not improbable that the individuals of the 

 second group were of mixed blood, possibly the result of 

 crosses with common mice. 



As I shall hope to make clear in a subsequent discussion 

 of the dancer's peculiarities of behavior, in a chapter on 

 individual differences, there is no sufficient reason for doubt- 

 ing the general truth of Cyon's description, although there 

 is abundant evidence of his inaccuracy in details. If, for 

 the present, we accept without further evidence the statement 

 that there is more than one variety of dancer, we shall be able 

 to account for many of the apparent inaccuracies of descrip- 

 tion which are to be found in the literature on the animal. 



As a result of the examination of the facts which this 

 chapter presents we have discovered at least six important 



