Ecuador and Venezuela. 453 



loins, but there is little difference over the rest of the upper 

 surface. Projecting tips of longer hairs whitish. Belly not 

 sharply defined, the hairs slate-coloured except at their ex- 

 treme tips, which are huffy. Ears scarcely projecting from 

 the long fur of the head, the anterior third of their outer 

 surfaces black. Metapodials brown mesially, whitish laterally, 

 as are also tlie digits. Tail shorter than in yE*. lugens, barely 

 as long as the head without the body, finely scaled, short- 

 haired, brown througliout. 



The skull of the type is unfortunately very imperfect, but 

 it differs from that of jE. lugens by its shorter nasals and 

 rather broader anterior zygoma-root. The slanting shape of 

 the latter is quite as in the type species. 



Dimensions of the type (measured in skin) : — 



Head and body 111 millim. ; tail 84; hind foot without 

 claws 25 ; ear (approximately) 13. 



Skull : length of nasals lO'l ; interorbital breadth 6 ; 

 diastema 7*5 ; palatal foramina 5'5x 2' 1. Lower jaw : con- 

 dyle to incisor-tips 18*1 ; length of lower molar series 5" 7. 



Bab. Mount Pichincha, Ecuador, at about 12,000 feet. 



Ti/pe : B. M. no. 98. 5. 1. 10. Killed May 1897. 



jE. vulcani may be distinguished from its ally jE, lugens 

 by its longer softer fur and much shorter tail. 



Thomasomys paramorunij sp. n. 



Considerably smaller than T. cinereus. Fur long, soft, 

 and woolly, the hairs on the back about 15 millim. in length- 

 General colour, so far as can be made out in a spirit-specimen, 

 dark rufous brown ; belly dull whitish, not sharply defined. 

 Ears large, evenly rounded, without anterior basal projection, 

 well-haired, dark brown. Hands and feet white above, 

 without darker metapodials. Tail long, well-haired, the hairs 

 almost hiding the scales, but not specially pencilled at its 

 tip ; brown above, rather lighter below, but not markedly 

 bicolor. Mammae 1 — 2=6. 



Skull slender and very delicately built, the bones of the 

 brain-case exceedingly tliin and papery. Muzzle narrow. 

 Interorbital region paiallel-sided, narrow, its edges rounded, 

 without ridges, though it is flattened mesially. Brain-case 

 long, narrow, smoothly rounded. Front edge of zygoma-root 

 nearly vertical, without projection. Palatal foramina long, 

 reaching backward to the level of the front lamina of m}. 

 Bullas larger than in T. cinereus. Incisors narrow, dark 

 orange in front. Molar structure much as in T. cinereus^ 

 m.^ distinctly 6-cusped, not 5-cusped as in Peromyscus. 



