442 



THE ZOOLOGIST. 



foot, 24 mm. Ear, 18 mm. For the purpose of comparison, 

 I will here give a few measurements of Mus sylvaticus and 

 M. Jlavicollis, adult mice with worn teeth, and young in the 

 grey plumage. All figures are in millimetres, and taken from 

 specimens in the flesh by myself. The ear is measured from the 

 notch, and the length of the hind foot does not include the claw. 

 The measurement of the head and body -f- the tail may be relied 

 on as giving the total length of the animal. 





MUS SYLVATICUS. 



MUS FLAVICOLLIS. 



Sex, ad 



? 



93 

 17 

 22 



86 



$ 



83 

 16 

 22 



75 



2 

 92 

 16 

 22 

 82 



$ 



83 

 16 

 21 

 79 



2 



92 

 17 

 22 



78 



9 

 71 

 16 



20 

 59 



97 

 17 

 23 

 85 



9 



108 

 18 

 24 



108 



? 



81 

 16 

 21 



84 



9 



110 

 18 

 23 



115 



9 



84 

 16 

 22 



83 



<? 



110 

 18 

 24 



112 



$ 



68 

 16 

 20 

 60 



9 



115 



18 



24 



112 



Head and body . 

 Ear 



Hind-foot 



Tail 



Sex, juv 



Head and body . 

 Ear 



Hind-foot 



Tail 











All the specimens above measured were caught within an 

 area of thirty acres, but the species did not intermingle ; yet there 

 was no natural boundary or observable difference in the soil on 

 which they were found. 



In comparison with Mus sylvaticus, the general colour of the 

 upper parts in M. Jlavicollis is brighter, especially along the sides 

 and legs, and the under parts of almost pure white, excepting 

 the gorget or breast-plate of clear yellowish brown (from which 

 it takes its specific name) ; this band is about 8 mm. broad, 

 passing across the chest, immediately in front of the fore legs, 

 with a cross or longitudinal stripe in the centre extending forward 

 about 5 mm., and back along the sternum about 10 mm., where 

 it is entirely lost, unlike the slight dash of colour so frequently 

 found on the chest of Mus sylvaticus, and which varies from the 

 smallest spot on the breast to a decided yellow-brown tinge 

 extending over the whole belly. 



The richer colouring of the upper parts in Mus jlavicollis, 

 and the pureness of the white on the under side, with the very 



