MAMMALIA. 



87 



soft ; general colour gray faintly washed with yellow ; under parts of the body 

 grayish white; feet dirty white; tail dusky, paler beneath at the base: 

 the ears are large, distinctly emarginated behind, and appear to be almost 

 naked, but, upon close examination, long and extremely fine hairs may be 

 observed. All the fur is gray at the base ; the hairs of the moustaches 

 are numerous and very long, those nearest the mouth are white, the others 

 are black at the base and grayish beyond. The incisors are of a palish 

 yellow colour. 



In. Lines. 

 6 6 



2 10 

 1 4 



Length of tarsi (claws included) 



of ear 

 Width of ear 



In. Lines. 

 1 1 



7 

 7i 



Length from nose to the root of tail 

 of tail .... 



from nose to ear 



Habitat, Chile, {September.) 



This species is about one-third the size of the last, it differs moreover in being 

 gray instead of brown, and in having the posterior margin of the ear emarginated ; 

 the tail is also rather shorter in proportion. 



The skull* is figured in Plate 33, fig. 1, a, and 1, b ; and fig. 23, a, Plate 34. 

 Its length is 1 inch, 4£ lines ; width &J. lines ; length of nasal bones 6 lines ; dis- 

 tance between fore part of incisors and the front molar (upper jaw) 5 lines ; longi- 

 tudinal extent of the three molars of upper jaw 3 lines ; length of auditory bulla? 

 51 lines; length of ramus of lower jaw (see Plate 33, fig. 1, c,), without incisors, 

 11| lines. Fig. 23, c, Plate 34, represents the inner side of a ramus of the lower 

 jaw : fig. 1, d, Plate 33, is the lower jaw seen from above : fig. 23, b, Plate 34, is 

 the same seen from beneath. This view is given to show the position of the 

 descending ramus of the lower jaw — that it springs from the outer side of the 

 alveolar portion, as in a great portion of the South American Rodents, such as 

 Dasyprocta, Myopotamus, Echimys, Chinchilla, and also in that genus found in the 

 West Indian islands, Capromys. Fig. 1 , e, Plate 33, represents the molar teeth 

 of the upper jaw, and fig. l,f, those of the lower. 



" This species is abundant on the dry hills, partly covered with bushes, 

 near Valparaiso." — D. 



* The skull is, unfortunately, imperfect, the hinder portion is injured, and the arches which enclosed the 

 ant-orbital openings are broken. 



