306 Mr. O. Thomas on new Mammals 



Hah. La Oya del Barro, W. Cundinamarca, Colombia. 



Type collected Sept. 2, 1895. 



The resemblance of this species externally to 0. laniger is 

 so great that practically the only means of distinguishing 

 the two lies in the brownish feet or, rather, metatarsals of 

 O. laniger as compared w4tli the silvery-white ones of the 

 new form. The skulls, however, are wholly different from one 

 another both in size and proportions. 



Oryzomys (?) lugens, sp. n. 



Very similar in all respects to the peculiar 0. tncanus 

 described recently from Peru *. Fur soft, close, and velvety. 

 General colour finely grizzled olive -brown, but little lighter 

 below than above. Ears large, brown. Hands and feet 

 slender, thinly haired, brown above, the hairs at the bases of 

 the claws wdiitish. Tail about the length of the head and 

 body, uniformly thinly haired, brown above, rather lighter 

 below. 



Skull in shape almost su2;gesting that of an Oxymycterus 

 or Acodon. Muzzle long, cylindrical. Interorbital convex 

 above and rounded laterally, without trace of ridges ; indeed, 

 a section through the nasal chamber between the orbits would 

 present an almost circular outline. Brain-case narrow, 

 smoothly rounded. Zygomata very slender, little expanded, 

 their anterior root narrow, slanted, without projecting plate. 

 Palatine foramina extending back to the level of the front of 

 ?^. Lower jaw very slender, matching that of 0. incanus. 

 Molars rather Acodont in appearance, with comparatively 

 high crowns ; ^n with its anterior lamina unicuspid, so as to 

 present only five cusps in all. 



Measurements of the type (an adult female in skin) : — 



Head and body 114 millim. ; tail 118; hind foot 27; 

 ear 17. 



Skull : basal length 26 ; basilar length from henselion 24 ; 

 greatest breadth 14'8 ; nasals 12*2 x 3*8 ; interorbital breadth 

 6; breadth of brain-case 12"8; anterior zygoma-root 2*1; 

 length of palate from henselion 13*2; diastema 8*3; palatine 

 foramina 5*9 x 2*6 ; length of upper molar series 4-8. Lower 

 jaw : condyle to incisor-tip 19"7. 



Hah. La Loma del Morro, near Merida, Venezuela, alt. 

 3000 metres. 



Coll. S. Briceno, May 18, 1896. 



" Eyes black, excessively small. Makes its nest in trees." 

 — S. Briceno. 



* Ann. & Mag. Nat. Hist. (6) xiv. p. 350 (1894). 



