new South-American Mammals. 153 



brain-case ]7'5xl3*5; palate length from henselion 13*1 ; 

 diastema 87; palatal foramina 6*6 x 2-5 ; length of upper 

 molar series 5. 



Hob. Merida. Type from " Las Vegas del Chama," alt. 

 1400 m. 



Ti/pe (female). B.M. no. 99. 12. 1. 1. Collected 14th July, 

 1896, by S. Briceno. 



Three skins of tliis species have been lying for some time 

 among Sr. Briceno's specimens of Bh. venezuelfe, to wliich I 

 had supposed them to be referable. Now, however, a closer 

 examination shows that tiiey belong to quite a different 

 species, distinguished by the characters above mentioned. 



Neacomys, gen. nov. 



T^pe. Ort/zomt/s spinosus, Thos. P. Z. S. 1882, p. 10.5. 



Further knowledge of South-American Muridae having 

 failed to reveal any species of " Oryzomys " intermediate 

 between the Acomys-Yikt " IJesperomys " spinosus described 

 by me eighteen years ago and the ordinary soft-furred species 

 of Oryzomys, I now think it advisable to give that anomalous 

 form a special generic name. 



To the cranial characters described previously it may be 

 added that the skull is low and broad, the supraorbital 

 edges distinctly but not excessively beaded, the interparietal 

 of medium size, the bullre small, and the palatal foramina are 

 unusually short. The molars are of typical Oryzomys structure, 

 but are small in proportion to the general size of the skull. 



Neacomys spinosus tenuipes, subsp. n. 



Very similar to N. s. typicus in general appearance, spini- 

 ness, and colour, but the general tone rather less vivid, the 

 back darker, and the sides shading off into fulvous rather than 

 rufous. Belly-hairs pure white or dull white, not slate-based, 

 though this latter characteristic proves to vary in A'^. s. typicus. 

 Feet very much smaller than in typicus, averaging about 

 2 millim. shorter, and very markedly more slender than in 

 that form. 



Dimensions of the type (an adult female, measured in 

 skin) : — 



Head and body 76 millim, ; tail 93 ; hind foot 20; ear 12. 



Hab. Guaquimay, near Bogota. Also from " Qiiebrada 

 negra " and " Magdalena Valley." 



Type. B.M. no. 99. 10. 3. 74. Collected by G. D. Child, 

 16th January, 1896. Five specimens examined. 



Five specimens of the typical form from Peru have the 

 hind feet 22-2, 22-2, 22-4, 22-6, and 23 millim. ; the longest 

 foot among the Bogota series is 20"5 millim. in length. 



