36(3 NOTES 



The "singing" individual was, so far as could be ascertained, 

 a common house mouse (Mus musculus). She was somewhat 

 larger than the ordinary wild female, but no other external 

 peculiarities were noted. She was extremely active and savage 

 and her mate always bore the marks of her teeth. An attempt 

 to mate her with a second tame male resulted in the death of 

 the latter. 



No definite time for "singing" was" noted, except three or 

 four days before and for six or seven days after the birth of 

 a litter. It was observed, also, that the individual "sang" 

 sometimes when frightened. 



The sound is best described as a rapid whole-toned trill in- 

 volving the tones c and d, as is indicated below. 



g >j jj g %) g|g 



The quality of the tone resembled somewhat that of a fife 

 or Mute, but each tone ended with a slight throaty click. The 

 tones were uttered at the rate of four or five per second in groups 

 of varying size. Sometimes, a group occupied one second, some- 

 times as long as ten seconds. As a rale, the tones of a group 

 were not clear and distinct but, instead, were uttered so rapidly 

 as to seem connected. The throaty click was more noticeable 

 in the case of the last tone of a group. Often the "singing" 

 would be continued for a period of ten or fifteen minutes with 

 rests between groups. 



The sound could readily be heard at a distance of fifteen or 

 twenty feet, but it was difficult to localize it. The individual 

 "sang" little during June, iqi 2, and it was not heard after 

 July 1st, 1 91 2. She died in August, apparently of old age. 



During May, 191 2, "singing" was again heard in the room in 

 which the "singing" mice had earlier been captured, I ut efforts 

 to capture the "singer" failed. 



