Ill 



THE AMERICAN NATURALIST [Vol. LIV 



There would appear to be also some resemblance to the 

 tumbling and shaking of the Fantail (French Trembleur). 

 Eiddle states that the " character is, with some irreg- 

 ularities, a Mendelian recessive." His inference that it 

 may have been produced by " reproductive overwork" 

 seems inconclusive. 



In connection with experiments on the homing ability 

 of pigeons Hurst (1913) speaks of obtaining "feeble- 

 minded" birds, as follows: 



Results show that incompetent or feeble-minded pigeons may be 

 bred from competent or intelligent parents, and it is interesting to find 

 that feeble-mindedness behaves as a recessive character in birds as well 



Fortunately, or unfortunately, it is much more difficult to get off- 

 spring from the feeble-minded in Pigeons than in Man. 



Mouse and Rat. — The well-known "waltzing" of the 

 waltzing mouse is probably of the nature of a nervous 

 disorder, either directly or indirectly. It is a simple 

 Mendelian recessive. 



Bonhote (1912) at a meeting of the Zoological Society 

 of London "exhibited living specimens of rats (Mus 

 rattus) which he had bred in the course of his exper- 

 iments, and which showed the 'waltzing' character well 

 known in a variety of the domestic mouse, but which had 

 not hitherto been recorded in rats." 



Rabbit. — We have in our possession a rabbit which is 

 now several years old, and which has since it was young 

 exhibited characteristic circus movements, or "waltzing," 

 very similar to the activities of the waltzing mouse. This 

 character appeared sporadically and we have been unable 

 to find that it is heritable, even though we have repeat- 

 edly bred this male's daughters to their own brothers and 

 back to him. He appears normal in other respects except 

 that one eye seems somewhat distorted, which may have 

 something to do with his behavior. This case differs 

 from the waltzing mouse in that it is probably not her- 

 itable, and certainly is not a simple Mendelian recessive. 



Guinea-Rig. — Some of the various defects in guinea- 



