194 Mr. O. Thomas on 



S. (M.) similis, Nels.*, from Call, Colombia, of wliicli the 

 Museum ]>ossesses a skull, differs by its uuusually slender 

 incisors, these being only T-l millim. in depth as against 2*0. 

 S. chrysurusj Puch.t, the only other allied species, may be 

 distinguished by its golden or ferruginous tail. 



Ueteromys australis, sp. n. 



A large dark species, with naked soles, allied to //. melano- 

 leucus. 



Fur close and crisp, rather short, spines about 8 millim. 

 long by 0*5 millim. broad. General colour dark smoky grey, 

 as in the allied species, the hairs of the back finely tipped 

 with yellowish, the spines greyish white with black tips. 

 Ears short, practically naked, black, finely edged with white. 

 A tuft of stiff hairs just in front of the ears black, but in some 

 cases white. Muzzle, throat, pouches inside and out, belly, 

 and inner sides of limbs white. Lower part of forearms 

 indistinctly slaty greyish all round, which colour runs on to 

 the median part of the metacarpals, the remainder and the 

 digits white. Posteriorly also the metatarsus is indistinctly 

 brown, the toes being white. Tail thinly hairy, the rings of 

 scales showing through, brown above, white below, the two 

 colours not sharply defined. 



Skull stoutly built, broad iu proportion to its length ; its 

 detailed characters apparently much as in the allied species. 

 Dimensions of the type (measured in the flesh) : — 

 Head and body 135 millim. ; tail ll>7 ; hind foot, s. u. 30, 

 c. u. 33 ; ear 15. 



Skull : greatest length 35 ; basilar length 24*5 ; zygomatic 

 breadth 17; length of nasals 14"2 ; interorbital breadth 9'2 ; 

 interparietal 4' 7 X 9*5 ; length of j)alate from henselion 14*2 ; 

 diastema 9 ; length of upper molar series (crowns) 4'5. 



IJab. St. Javier, Lower Cachabi River, N. Ecuador. Alt. 

 20 m. ^ 



Type. Female. Original number G4. (Collected 23rd 

 June, 1900, by G. Flemming and R. Miketta. Fourteen 

 specimens examined. 



This is by far the most southern record for the genus 

 Heteromys, and is the first discovery of any member of the 

 genus to the west of the Andean chain. The species is allied 

 to the dark naked-footed species H. longicaudatus^ anomalus, 

 melanoleucus, &c., but seems to be different from any of them. 

 Among other characteristics its partially dark metapodials 

 would alone distinguish it, as the other members of the group 

 have these parts wholly white. 



* Bull. Am. Mus. N. H. xii. p. 78 (1899). 

 t ' Revue Zoologique,' 1845, p. 337. 



