278 Bulletin American Museum of Natural History. [Vol. XXXIV, 
Urosciurus langsdorffii urucumus (Allen). 
Sciurus langsdorffit urucumus ALLEN, Bull. Amer. Mus. Nat. Hist., XX XIII, 
p. 595, Sept. 8, 1914. 
Type locality.— Urucum, Rio Paraguay (at mouth of Rio Tacuary), 
Matto Grosso, Brazil; altitude 400 feet. 
Geographic distribution. Known only from the vicinity of the type 
locality, in southwestern Matto Grosso, Brazil. 
Description.— “Similar in general to S. langsdorffic langsdorffir, but 
much smaller and darker colored, with much blacker tail. Upperparts 
dusky brown, the hairs brownish black minutely tipped with yellowish; 
nose and front of head pale orange with a narrow median stripe of black 
on the nose; lower back and rump with tips of the hairs inclining to dark 
rufous; ears externally blackish edged with rufous; postauricular patch 
of soft rufous hairs conspicuous; underparts nearly uniform ochraceous buff; 
fore limbs and feet externally grizzled buff and black; hind limbs externally 
light chestnut, feet grizzled dark rufous and black; tail above for the basal 
fourth intense black, usually a few of the hairs tipped with chestnut; rest 
of the upper surface of tail pale orange, the hairs black for the greater part 
of their length, tipped with pale orange, through which the black basal por- 
tion of the hairs is more or less visible; tail below for the basal third or more, 
and medially often nearly to the end, intense black, fringed with orange for 
the apical two thirds and at the tip. 
“Total length (type, collector’s measurements), 500 mm.; head and 
body, 260; tail vertebree, 260; hind foot, s. u., 60, c. u., 63. Six adults 
(all topotypes), total length, 502 (490-530), head and body, 251 (240-260); 
tail vertebree, 250 (230-260); hind foot, c. u., 60.5 (60-63). 
“Skull (type), total length, 57; zygomatic breadth, 35.2; interorbital 
breadth, 19; postorbital breadth, 18; breadth of braincase, 23.2; nasals, 
17 X 7; diastema, 16; maxillary toothrow, 8.5. Seven skulls (type and 6 
topotypes), total length, 59 (57-61); zygomatic breadth, 35 (34.6-36) ; 
interorbital breadth, 19.6 (19-21); postorbital breadth, 18.3 (18-19); 
breadth of braincase, 23.4 (22.6-24); nasals, 18.3 X 7.4 (17.5-19 X 7-8); 
diastema, 16 (16-18); maxillary toothrow, 8.8 (8.3-9.2).” — Allen, J. c. 
Specomens examined, 11.— Brazil: Urucum, 7; Tapirapoan, 4 (Am. 
Mus., Roosevelt Exped.). 
Remarks.— The type locality is about 350 miles south of Cuyaba, the 
type locality of langsdorffii. While the external measurements (on the basis 
of collectors’ measurements) of uwrucumus seem to slightly exceed those of 
either langsdorffit or steinbachi, the skulls are markedly smaller, with nar- 
