I02 NATURAL SCIENCE. August, 1895. 



before it was noticed. Like ordinary mice they sleep during the day, 

 but apparently waltz the whole night long. If, however, they are 

 disturbed during daylight, they leave their bed and work off some 

 surplus energy. 



The rotation is so rapid that all individuality of head and tail is 

 lost to the eye, only a confused ball of black and white being recog- 

 nisable. Very often they spin in couples, revolving head to tail at 

 such a speed that an unbroken ring only is perceived. It is re- 

 markable that they keep perfectly together ; this may be attributed 

 to their similarity in size and not to any special faculty they may 

 possess. An upright peg forms a favorite pivot, but even without 

 this guide they would not, in several minutes, cover an area larger 

 than a dinner plate, and they easily spin under a tumbler. Some- 

 times three or four mice run together, the extra ones then form an 

 outer circle, but as the evident desire is to rotate rather than revolve, 

 more than two seldom work well. An individual generally spins in 

 one direction only, and the majority turn to the left, only a small 

 proportion going " with the clock." 



A waltzing mouse may be placed on the ground without fear of it 

 escaping. Should it attempt to do so, it will not proceed far before 

 being seized with a paroxysm, which it will be necessary to work off 

 before further progress can be attempted. These mice may also be 

 kept in a paper box, which would not detain a wild mouse an hour ; 

 the process of gnawing the walls of their prison will be so frequently 

 interrupted by the necessity of practising their infirmity that little 

 damage can be done. As with all truly domestic mice, however, no 

 determined effort to escape, such as characterises the wild mouse, is 

 ever attempted, and at most such efforts are to be regarded as an 

 inherited habit rather than a real desire for liberty, for domestic mice 

 do not readily leave when their cages are left open. 



The feature of the breed may be due to cerebral derangement, 

 but that the trait is, at the present day, purely hereditary and not 

 acquired by the individual, is shown by the fact that as soon as 

 they arrive at an age when other mice begin to run, these begin to^ 

 waltz. 



They may be compared to tumbler pigeons, and the analogy 

 is close, allowing for differences between an aerial and a terrestrial 

 performance. The plane of motion is, however, quite different, as 

 exemplified by Indian ground tumblers, which, when placed on the 

 ground, turn head over heels.' In both cases the affection is the result 

 of perpetuation by heredity of an affliction which would have insured 

 the destruction of a wild race. 



Edgar R. Waite. 

 Australian Museum, Sydney, 

 2yih March, 1895. 



^Darwin. "Plants and Animals, etc.," i., p. 150. 



