The molars of the upper jaw are figured in Plate 34, fig. 13, a, and those of the lower jaw, fig. 13, b.

“Caught in the interior plains of Patagonia in lat. 50°, near the banks of the Santa Cruz.”—D.

23. Mus griseo-flavus.
Plate XXI.

Mus griseo-flavus, Waterh., Proceedings of the Zoological Society of London for February 1837, p. 28.

M. suprà griseus flavo-lavatus, ad latera flavus, subtùs albus; pedibus albis; auribus magnis et ferè nudis; caudâ caput corpusque ferè æquante, suprà fusco-nigricante, subtùs albâ; vellere longo, molli.

Description.—Ears large; tail rather shorter than the head and body taken together; tarsi slender, and moderately long; fur long and very soft; general tint of the upper parts of head and body grayish, washed with brownish yellow; on the sides of the body a palish yellow tint prevails; feet, chin, throat, and under parts of body pure white; tail rather sparingly clothed with hairs, those on the apical portion rather long, and forming a slight pencil at the tip; on the upper side and at the tip of the tail the hairs are brown, on the under side they are dirty white; the ears are very sparingly clothed with minute brownish yellow hairs internally; externally, on the fore part, the hairs are rather longer and of a brown colour; the upper incisors are orange, and the lower incisors are yellow; the hairs of the moustaches are long, and of a black colour; the hairs of the back are deep gray at the base, brownish at the tip, and annulated with pale brownish yellow near the tip; the longer hairs are brown; the hairs of the belly are white externally, and gray at the base; on the throat the hairs are white to the root.

In.Lines.
Lengthfrom nose to root of tail68
of tail56
from nose to ear14½
of tarsus (claws included)12½
of ear08

Habitat, Northern Patagonia (August.)

The molars of the upper jaw are figured in Plate 34, fig. 15, a, and those of the lower jaw, fig. 15, b.

“Inhabits the dry gravelly plain, bordering the Rio Negro.”—D.