54  Frecp Museum or Naturat History — Zoéxoey, Vor. X. 
without scales; the upper side of the hind feet, however, is unusually 
scaly and the scales being dark colored with lighter margins and but 
slightly overlaid by hairs, they are quite obvious. The skull is peculiar 
in shape and the dorsal view reminds rather forcibly of immature skulls 
of Evotomys. Aside from the forwardly projecting incisors, there are 
certain slight dental peculiarities not easily described, but it may be 
mentioned that the second upper molar is as wide as long and its outer 
side is markedly external to the outer sides of M! and M®. Another 
unusual feature is a pair of swollen ridges lying on either side of the 
palatine foramina ‘and in front of M!. So far as I am aware, with 
the exception of the type in the British Museum, no other sais (oi, of 
this interesting genus have been recorded. 
Sigmomys alstoni Thomas. False Cotton Rat. 
Seven specimens, El Panorama, Rio Aurare (4), Empalado Sav- 
annas (3). 
These were taken about the roots of cacti and small thorny 
shrubs and among crumbling exposed rocks in decidedly dry situations 
but always closely adjacent to grassy openings. They are evidently 
diurnal as practically all were caught in the day time. The exact type 
locality of this species is unknown but specimens from Cumana are 
regarded as typical by Thomas.* Whether our specimens differ from 
these cannot be determined except by comparison. 
Heteromys anomalus brachialis subsp. nov. White-armed Spiny 
Pocket Mouse. 
Type from El Panorama, Rio Aurare, eastern shore of Lake Mara- 
caibo, Venezuela. No. 18623 Field Museum of Natural History. Adult 
female. Collected Jan. 19, 1911, by W. H. Osgood and S. G. Jewett. 
Characters. Similar to Heteromys anomalus jesupi but upper parts 
paler and front legs nearly all white; dark marking on outer side of 
arms reduced to a few scattered grayish hairs widely separated from 
the main body color by pure white. Ground color of upper parts drab 
somewhat brightened in middorsal region by wood brown and cinna- 
mon; rump grayish drab or hair brown continuing along outer side of 
hind legs to caleaneum; feet white; tail grayish drab above, white below; 
ears narrowly edged with whitish. 
Skull practically as in H. anomalus and H., a. jesupi. 
Measurements. Type: Total length 284; head and body 134; 
* Ann, & Mag. Nat. Hist. (7), VIII, p. 150, footnote, roor. 
