6s8 MURID^— MUS 



The Japanese have cultivated a breed of tame House Mice 

 remarkable for their habit of running round and round in 

 circles when in the open, whence they are called "dancing 

 or waltzing mice." In 1894 William Blasius showed specimens 

 to Barrett- Hamilton, and inforined him that two or three 

 will join to make one composite circle, and thus have a 

 tendency to damage each other's tails ; in apparent proof 

 of which, Barrett-Hamilton noticed that the old mice had 

 no tails, whereas a young one was well provided. These mice 

 appeared to be tame white mice marked with black. Waltzing 

 mice of various colours are known ; in some the eyes are 

 black, in others pink ; the pink-eyed types breed true to that 

 character. When exposed to light, such mice run round after 

 their tails, spinning with great rapidity. Very often, if not 

 invariably, the waltzing habit is correlated with a malformation 

 of the internal ear, and "waltzers" are always of delicate 

 constitution ; but the physiological cause of the habit is not 

 well understood at present. From the experiments made by 

 Von Guaita and Darbishire it would appear that "waltzers" 

 behave as complete recessives when crossed with normal non- 

 waltzing types.^ 



It is of interest to note that " waltzing black rats " appeared 

 in the course of Bonhote's breeding experiments, with the 

 progeny of a cross between E. r. alexandrinus and E. r. 

 frugivorus {Proc. Zool. Soc, 191 2, 6). These also proved to 

 be very delicate. 



The nest of the House Mouse is composed of soft materials 

 such as straw, hay, woollen and cotton rags, or paper ; these 



Nature, xvii., 1877, 11 ; J. Sidebotham, ibid., 29 ; G. J. Romanes, ibid., 29 ; Landois, 

 Zool. Gart, 1871, 162, axiA Jahresb. Westfal. Verein., xi., 1882-3, '7 ^"d 21 ; Struck, 

 Arch. Ver. Mecklenburg, xxxv., 117; Lataste, Zooethique, 1887, 287; Lockwood, 

 Amer. Nat, 1871, v., 761 ; Darwin, Descent of Man, 568, 865 ; A. H. Cocks, Bucks; 

 Douglas English, Some Smaller British Mammals, 84 ; Coburn, Joum. An. 

 Behaviour, ii., 1912, 364, and iii., I9I3,''388 ; and T. Coward, in lit., to Barrett- 

 Hamilton, 2nd July 1912. Numerous other references will be found in some of 

 the papers cited— notably in those of Landois and Struck. 



' See Von Guaita, Ber. Naturf. Ges. Freiburg., x., 1898, 317, and xi., 1900, 131 ; 

 Darbishire, Biometrika, ii., 1902, loi, 165, 282, and iii., 1903, i ; Durham, Rep. 

 Evol. Comm. Roy. Soc, iv., 1908, 41 ; Bateson, Mendel's Principles of Heredity, 

 1909, 33 and III ; Alexander and Kreidi, Monatschr. Ohrenheilk., Berlin, 35, 1901, 

 78 ; Yerkes, The Dancing Mouse, New York, 1907 ; Quix, Amsterdam, Werk. Gen. 

 Nat. Genees. Heelk., 1909, 83. 



