57 



MAMMALIA. 



the yellow tint prevails ; on the under parts of the body the hairs are broadly 

 tipped with pale yellow, and in parts with white: the tail is but sparingly 

 clothed with hairs, those on the upper surface are of a dark brown colour, and 

 those on the under are pale brown. The incisors are very slender and ot 

 a very pale yellow colour. 



In. Lines. 



Length of tarsus (claws included) . . 1 5 



of ear 



5 



In. Lines. 

 Length from nose to root of tail . .52 



oftail 2 8 



from nose to ear . • .13 



Habitat, Maldonado, La Plata, (June.) 



The specific name nasutus has been applied to this mouse on account of 

 its elongated and slender muzzle*, the tip of which extends nearly 4 lines 

 beyond the upper pair of incisors : the rudimentary toe of the fore foot, instead 

 of having the usual rounded nail, has a short pointed claw. Its fur is not 

 so soft, nor yet so long as in many of the preceding species, and there is a 

 greater admixture of yellow in its colouring. The claws appear to be adapted to 

 burrowing. 



The skull (which is not quite perfect) is figured in Plate 33, fig. 7, a, its 

 length is 1 in. 3 lines. Fig. 7, b, represents the molars of the upper jaw, and fig. 

 7, c, those of the under jaw. The lower jaw, which is of a very slender and elon- 

 gated form, is figured in Plate 34, fig. 10, a. 



" Was caught in a small thicket on an open grassy plain, by a trap baited 

 with a piece of bird. This mouse when alive possesses a marked character in the 

 extreme acumination of its nose." — D. 



20. Mus TUMIDUS. 



Plate XVIII. 



Mus tumidus, Waterh., Proceedings of the Zoological Society of London for February 1837, p. 15. 



M. brunneus, nigro lavatus ; rostro ad apicem, labiis, mento, guld, pectore, abdomineque 

 albis; naso suprh nigrescente ; auribus mediocribus rotundatis ; corpore crasso ; caudd 

 capite corporeque breviore, pilis nigricantibus, subtus albescentibus prope basin, ves- 

 titd; ar tubus pedibusque grisescentibus ; vellere longo, molli; unguibus longis. 



Description. — Body stout ; head large ; tail nearly as long as the head and body; 



* In Mus longipilU and M. brachiotis may be perceived an approach to this elongated form of the muzzle. 



I 



