_M. suprà fusco-nigrescens, subtùs griseus; pedibus fuscis; auribus mediocribus, caudâ, quoad longitudinem, caput corpusque ferè æquante: vellere longissimo, molli._ DESCRIPTION.—Form stout; ears moderate; tail equal to the body in length; tarsi moderate; fur very long. General tint of the upper part and sides of the head and body blackish brown with an admixture of gray; of the under parts grayish white; feet brown, the hairs grayish at the tip: tail black and but sparingly clothed with short bristly hairs: ears rather sparingly clothed with hairs, which are for the most part of a brownish gray colour. The ordinary fur of the back is about ¾ of an inch in length and very soft—of a deep gray colour, broadly annulated with brownish yellow near the tip and blackish at the tip: the longer hairs which are black, measure upwards of 1¼ inches in length. The upper incisors are of an orange colour and the lower are black. In. Lines. Length from nose to root of tail 6 6 of tail 4 3 from nose to ear 1 6 of ear 0 6½ of tarsus (claws included) 1 1 Habitat, Australia, King George’s Sound, (_March_.) Mammalia not belonging to the order _Marsupiata_ are rare in the Continent of Australia. Besides the Dog, we are acquainted with none excepting a few species of Rodents, and these all belong to the family _Muridæ_. The present animal adds one to the limited number already known: in the Museum of the Zoological Society there is another species, the characters of which I will point out in the next description. _Mus fuscipes_ is remarkable for the great length and softness of its fur, and the brown colour of its feet: it is rather less than _Mus Rattus_, and of a stouter form. Not having had an opportunity of examining the molar teeth and the cranium of this animal, I cannot be positive that it is a species of the genus _Mus_; in external characters and the form of the incisor teeth, however, it agrees perfectly with the animals of that genus. “This animal was caught in a trap baited with cheese, amongst the bushes at King George’s Sound.”—D. 28. MUS GOULDII. _M. vellere longo, molli, ochraceo, pilis nigricantibus adsperso, his ad latera rarioribus: corpore subtùs, pedibusque albis: auribus majusculis: caudâ, capite corporeque paulo breviore._