234 Mr. O. Thomas on new Members of the 



Skull very similar to that of H. Salvini {ti/picus), but 

 rather smaller and more delicately built ; interparietal large, 

 its length 54 per cent, of its breadth ; upper incisors forming 

 a segment of a very small circle, so that their tips are much 

 bent inwards towards the mouth, and the diastema is propor- 

 tionally short. 



Dimensions of the type (a beautifully prepared ? skin) : — 



Head and body 104 millim., tail 113, hind foot 24-8, ear 

 from notch (contracted) 12. 



Skull: basal length 26-5, greatest length 31-6, greatest 

 breadth 15-2 ; nasals, length 12-7, breadth 3*6 ; interorbital 

 breadth 7-7 ; interparietal, length 4-6, breadth 8-5 ; diastema 

 7*7 ; length of upper molar series 4-3. 



Hab. Mineral San Sebastian, Jalisco, Mexico, 4300 feet. 

 Coll. Dr. A. C. Buller, May 9, 1893. 



Heteromys Salvini nigrescens, subsp. n. 



Colour very similar to that of H. S. typicus, but tlie 

 yellowish grizzling on the back, inconspicuous in that animal, 

 is entirely absent, at least along the mesial line, so that the 

 dorsal colour is a deep uniform smoky brown. Towards the 

 sides a few yellow-tipped hairs are present, but not in suffi- 

 cient numbers to affect the general tone. No trace of a 

 yellowish lateral line. Limbs as in H. 8. typicus. 



Skull decidedly smaller and more delicate than in the 

 typical form, the muzzle more slender, the interorbital region 

 narrower, and the interparietal conspicuously smaller (its 

 length-breadth percentage 51). 



Dimensions of the typical skin (B.M. 69. 7. 19. 6) : — 



Head and body 127 ; tail broken ; hind foot without 

 claws 25. 



Skull : greatest length 32*7, greatest breadth 15*4; nasals, 

 length 12"7, breadth 38; interorbital breadth 6'8; inter- 

 parietal, length 4*1, breadth 8; diastema 9*4; length of 

 upper molar series 4"7. 



Hab. Costa E-ica. 



Neotoma macrotis, sp. n. 



Intermediate in size between the western N. jloridana and 

 N. mexicana. Colour, so far as can be made out in a spirit- 

 specimen, very much as in the latter species. Belly-hairs 

 white-tipped. Feet white, faintly clouded proximally with 



