192 



RECORDS OF THE AUSTRALIAN MTTSEUM. 



Teeth. — The front edges of the upper incisors are of particularly 

 deep orange colour, the lower ones are somewhat paler. The molars 

 are relatively and actually larger than those of Mus decumanus, 

 and are noticeably broader ; the upper series converge anteriorly, 

 and are somewhat bowed outwards. 



Fia:. 2. 



Fig. 3. 



Fig. 4. 



The caudal vertebrae are twenty-five in number ; in the longer 

 tailed Mus arboricola {M. rattus, fide Thomas), the vertebrae 

 number thirty-eight. 



Waterhouse described the colour of the lower incisors as black, 

 evidently a peculiarity of the individual examined. Gray, writing 

 on Mus lutreola remarks, "front teeth yellow"; while Gould 

 says, "the incisor teeth are orange-coloured." I do not remember 

 having examined a rat's skull in which the incisor teeth are so 

 deeply tinted. The writers quoted describe the under parts of 



