from the Neotropical Region. 307 



As in the case of " Oryzomys " incanus, it is impossible to 

 assign a satisfactory position to this species, which differs in 

 nearly every respect from typical members of the genus ; but 

 without a far more extensive knowledge of South-American 

 Murines than is possessed at present, it would be unwise to 

 add to the number of named groups of what used to be called 

 " Hesperomys.'^ Without doing this, however, I frankly 

 confess myself incapable of finding a proper place for the 

 present animal, and merely put it nominally under the 

 heading of Oryzomys as a temporary expedient. Its slender 

 form and long tail separate it from Acodon, its nail-clad 

 pollex and normal muzzle show that it is not an Oxymycterus, 

 while its narrow brain-case and rounded interorbital region 

 separate it from ail the ordinary species of Oryzomys. 



As a species 0. lugens seems really most closely allied to 

 0. incanus, from which it differs by its much narrower 

 brain- case, more rounded interorbital region, and differently 

 shaped zygomatic root. Externally it seems very similar, 

 but as the type of one is in spirit and the other in skin, an 

 accurate comparison of the quality and colour of the fur is 

 not at present possible. 



Eligmodon* Moreni, sp. n. 



Size rather large as compared with the very small species 

 composing the group. Fur long and soft, but not woolly. 

 General colour above coarsely mixed fawn and brown, clearer 

 fawn on the sides. Belly, as usual, pure white or yellowish 

 white. (Immature specimens have the bases of the belly- 

 hairs slate.) Ears large, oval. Palate-ridges 3 — 5. Upper 

 sides of hands and feet silvery white. Palms and soles as 

 usual in the group, granulated, with a large more or less 

 hairy and corrugated pad at the base of the fingers and toes ; 

 a smaller more defined pad at the bases of pollex and hallux, 

 and another a little way behind the last-named. Tail longer 

 than the head and body, slender, thinly hairy throughout, 

 blackish above, white below and on the sides. 



Skull stoutly built, with a broad muzzle. Interorbital 

 region flat, its edges square, not beaded. Anterior palatal 

 foramina reaching backward one third the length of 5ii. 

 Posterior nares very narrow. 



Dimensions of the type (an adult male in spirit) : — 



Head and body 80 millim. ; tail 91 ; hind foot 23; ear 17. 



* Calomys, Waterh. (1837) nee Is, Geoff. (1830). 

 Eiigmodontia, F. Cuv. 1837. 

 Hesperomys, Waterh. 1839. 



