MAMMALIA. 



55 



unable to satisfy myself whether they are varieties of Mus xanthorhinus or 

 not. Both of Mus canescens and of Mus xanthorhinus, I have before me what I 

 imagine to be an adult and a young specimen. The adult and the young of 

 M. xanthorhinus agree in being of a yellowish-brown colour, and in having the 

 muzzle and tarsi deep yellow ; both specimens of Mus canescens are of a gray 

 colour, with an indistinct yellow wash, the muzzle and tarsi being tinted with 

 yellow, as in M. xanthorhinus. Besides this difference in tint, which, perhaps, 

 is unimportant, M. canescens differs from M. xanthorhinus in having the head 

 larger, the tail rather longer, and the fur less soft. The specimens of this animal 

 are both from Patagonia ; one of the specimens of Mus xanthorhinus was brought 

 by Mr. Darwin from Terra del Fuego ; and as the other formed part of Captain 

 King's collection, it in all probability came from the same locality. As I only 

 possess one skull, I cannot speak with certainty as regards the size of the head ; 

 the difference, however, in the stuffed specimens is considerable, and it is strange 

 that each of the pairs should agree so perfectly, supposing the difference to be 

 the work of the stuffer's hands. 



18. Mus LONGIPILIS. 



Plate XVI. 

 Mus longipilis, Waterh., Proceedings of the Zoological Society of London for February 1837, p. 16. 



M. supra, obscure griseus, Jlavo lavatus ; subtics griseus ; pedibus J'uscis, unguibus 

 longiusculis ; auribus mediocribus ; cauda corpore breviore, supra nigrescente, subtiis 

 fuscescente ; rhinario sub-producto : vellere longissimo, molli. 



Description. — Fur very soft and silky, and extremely long — the ordinary fur of 

 the back measuring nearly three quarters of an inch, and the longer hairs 

 one inch in length ; ears moderate ; tail nearly as long as the body ; muzzle 

 much pointed ; general colour gray, washed with yellow, the under parts 

 pale gray, or grayish white ; feet brown ; ears and tail well clothed ; the 

 hairs on the inner side of the ears are chiefly of a yellow colour, those on the 

 upper surface of the tail are brown black, those on the under part are dirty 

 white ; the hairs of the back are deep gray at the base, broadly annulated 

 with yellow near the apex, and dusky at the apex ; the longer hairs are 

 grayish black; the hairs of the moustaches are dusky at the base, and 

 whitish beyond that part ; the claws are long, and but slightly curved ; the 



