54 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. 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 Ml and ML Another 

 unusual feature is a pair of swollen ridges lying on either side of the 

 palatine foramina and in front of Ml. So far as I am aware, with 

 the exception of the type in the British Museum, no other specimens 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 calcaneum; 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, 1901. 



