THE COMMON MOUSE. 49 



Trans.,' vol. xviii.), belongs, as we have every reason 

 to believe, to the genus Hnpalotis (Lichtenst., ' Saugt." 

 pt. vi., 1829). It seems to take the place, on the open 

 plains of Australia, of the jerboas and gerbilles of the 

 deserts and plains of Africa and Asia ; or of the jumping 

 mice of North America. This singular species was found 

 on the reedy plains near the junction of the Murray and 

 Murrumbidgee, on the northern boundaries of Australia 

 Felix. The cut is taken from the figure in Sir T. 

 Mitchell's account of ' Three Expeditions into the In- 

 terior of Eastern Australia.' (Fig. 30.) Sir T. Mitchell 

 states that the fore and hind legs of this animal re- 

 sembled in proportion those of a kangaroo ; and it used 

 the latter by leaping on its hind-quarters in the same 

 manner. It was not much larger than a common field- 

 mouse, but the tail was longer in proportion than even 

 that of a kangaroo, and terminated in a hairy brush 

 about two inches long. We may here remark that the 

 genus Hapalotis is the same as Coniluriis, Ogilby 

 ('Linn. Trans.,' xviii., pt. i., p. 124, 1838), and must 

 be retained, according to the law of priority. 



The Common Mouse {Mus musculus). 



The genus Mus^ which includes the true rats and 

 mice, is typical of the extensive family Muridm, The 

 characters ofthis genus may be thus summed up: incisors 

 of the usual number ; those of the lower jaw compressed 

 and pointed ; molars on each side, both above and below, 

 three, with true roots, and a transversely tuberculated 

 surface, the ridges varying in number in each tooth ; 

 the anterior molar is the largest, the posterior the 

 smallest. (Fig. 31.) The muzzle is elongated and 

 sharp; the ears are oblong or rounded, and almost naked. 

 The toes of the anterior feet are four, with the minute 

 rudiment of a thumb; those of the hind-feet are five. 

 The limbs are short; the tail is long, cylindrical, taper- 

 ing, and annulated with scales of epidermis, from between 

 which emerge short hairs, forming a scanty covering. 

 The fur is soft, but traversed by long outer hairs of a 



