278 Mr. 0. Thomas on 



XXVII. — Descriptions of new Neotropical Mammals. 

 By Oldfield Thomas. 



Ti/lomys mirce, sp. n. 



Slightly larger than any of the other species. Fur close 

 and thick, the hairs about 20-23 mi Him. in length on the 

 back. General colour above dark cinereous grey, with a 

 slight tinge of fawn ; sides more grey and less fawn. Head 

 like body, area round eyes not darker. Ears apparently 

 rather small, naked, grey. Under surface white throughout, 

 tiie line of demarcation not very sharply defined ; on the belly 

 the white narrows, and some of the hairs have a slight greyish 

 tinge at their bases. Arms grey externally, white internally ; 

 legs grey nearly all round, but with a narrow line of white 

 running down to the ankles ; upper surface of hands and feet 

 cliocolate-brown, the terminal phalanges of digits and hairs 

 at the bases of the claws white. Terminal half of tail white, 

 the junction of the dark and white fairly abrupt all round, 

 little mottled. 



Nasals narrow, pointed posteriorly, scarcely surpassed by 

 the premaxillge; supraorbital ridges with a definite postorbital 

 angle, from which point they run nearly straight backwards 

 to the outer corners of the interparietal, and are but little 

 curved outwards in the parietal region. 



Dimensions of the type (an adult male, measured by 

 collector in the flesh) : — 



Head and body 230 millim. ; tail 266 ; hind foot (s. u.) 41 ; 

 ear 28. 



Skull : greatest length 54 ; basilar length from henseliou 

 42*5; greatest breadth 28; nasals, length 19; interorbital 

 breadth 11 ; breadth across most distant points of parietal 

 ridges (at postorbital processes) 20 ; palate length from 

 henselion 22*2; diastema 15; length of upper molar series 

 (teeth much worn) 8*8. 



Hab. Paramba, River Mira, N. Ecuador, altitude 1100 m. 



Type B.M. no. 99. 8. 25. 1. Collected by E. Miketta, 

 27th April, 1898. 



Three specimens examined, of which the first (an immature 

 female) was collected by Mr. W. F. H. Rosenberg on 

 March 4, 1897, also at Paramba. 



Tylomys Watsoni, sp. n. 



Size medium. Fur straight and glossy, about 15 millim. 

 long on the back. General colour above, both on head and 



