THE MOUSE TRIBE. i 39 



THE MOLE-LIKE VOLES. 

 Genera Ellobius and Siphneus. 



Certain representatives of the vole group are specially adapted for a sub- 

 terranean mole-like life, and, therefore, differ considerably from the other forms, 

 although they retain the ordinary type of molar teeth. In form they are 

 characterised by the' blunt and rounded head passing imperceptibly into the 

 cylindrical mole-like body, the absence of external ears, the short tail and limbs, 

 and the broad feet, each provided with five claws. The incisor teeth project 

 considerably, and their enamel is usually white, instead of having the yellow 

 or orange tinge so prevalent among the ordinary voles. 



These mole-like voles, of which there are but few species, are mainly confined 

 to Central and Northern Asia, although one species ranges as far south as 

 Afghanistan and Quetta, and another extends into Eastern Europe. They are 

 divided into two genera, according as to whether the claws of the fore-feet 

 are short or long; Ellobius including the short-clawed and Siphneus the long- 

 clawed species. The so-called Quetta vole (E. fuscicapillus) is about 5 inches in 

 total length, of which half an inch is occupied by the tail. It is brownish white 

 above, with the exception of the greyish brown head, while the under-parts, feet, 

 and tail are white ; the fur being long and soft. It is reported to construct 

 horizontal galleries in the ground, with heaps of earth thrown up at intervals, 

 after the fashion of the mole. 



THE RATS AND MICE. 



Genus Mus. 



The true rats and mice, together with certain allied forms referred to distinct 

 genera, are the representatives of the last subfamily of the Muridce, which is 

 exclusively confined to the Old World. They are primarily characterised by the 

 crowns of the unworn upper molar teeth carrying a number of tubercles arranged 

 in three longitudinal rows ; these teeth always having distinct roots. When worn 

 by use, the crowns of the molars exhibit transverse bands of enamel. The tail is 

 always long and scaly, and in most cases almost destitute of hairs. Moreover, 

 the ears are large, and the eyes bright and prominent, while the muzzle is sharply 

 pointed, and the build light and elegant. Their movements are quick, active, and 

 graceful, and their coloration is in most cases uniform and sombre, as would 

 naturally be expected from the nocturnal and burrowing habits of the majority 

 of the species. 



The Murine subfamily includes a considerable number of species, by far the 

 greater majority of which are comprised in the genus Mus. That genus is character- 

 ised by the incisor teeth being smooth, and the molars distinctly tuberculated. 

 The ears and eyes are proportionately large, and the tip of the muzzle is naked, 

 while the tail is long and scaly. The first toe of the fore-foot has a short nail in 

 lieu of a claw; and the fur is soft, although in some cases intermingled with 



