1915.| Allen, Review of the South American Sciurides 257 
the hairs black coarsely annulated near the tip with ochraceous rufous; a 
narrow yellow eye-ring; chin, throat, and inside of fore limbs grayish brown 
with a buffy wash; chest and abdomen orange or orange rufous; tail above 
black washed with orange, the hairs basally grizzled dull yellowish and 
black, subapically broadly banded with black and tipped with orange; 
tail not tipped with black; under surface of tail grizzled orange and black; 
feet dusky grayish brown minutely punctated with fulvous or rufous. 
Total length, 365 mm.; head and body, 180; tail vertebra, 185; hind 
foot (s. u.), 44, ec. u., 47. Skull, total length, 45; zygomatic breadth, 27; 
interorbital breadth, 16; breadth of braincase, 21; length of nasals, 12; 
diastema, 11; maxillary toothrow, 7. (Measurements of an old female 
from Bonasica, Essequibo River, British Guiana. For additional measure- 
ments see Table VII, p. 264). 3 
Specimens examined, 17.— British Guiana: Surinam River, 8; Bartica 
Grove, 3 (all Br. Mus., coll. F. V. McConnell); Kaieteur Falls, 1 (Am. Mus.); 
Potaro Landing, 2 (Am. Mus., 1; Brit. Mus. 1); Potaro Highlands, 1 (Br. 
Mus.). French Guiana: Ipousin, Approague River, 1 (Br. Mus.). 
Remarks.— Sciurus estuans was the first South American squirrel recog- 
nized in systematic zodélogy, it having been technically named by Linné in 
1766. His description was very brief and quite insufficient for satisfactory 
identification. The habitat of the species was given as “Surinam”; and 
by common consent the name has come to be assigned to one of the small 
squirrels of the Guianas. The name as employed for nearly a century was 
a ‘blanket name’ for practically all of the small squirrels of tropical America. 
The group has since been separated into numerous species and subspecies, 
some of them widely different from @stuans as now restricted. 
Typical estwans is poorly représented in the museums of this country; 
the present description is based on the series in the British Museum, but only 
one of them has measurements taken before skinning. 
There is, as usual, a considerable range of individual variation in colora- 
tion and size, but the above description is believed to represent the average 
conditions. 
Guerlinguetus estuans gilvigularis (Wagner). 
Plate IX, Fig. 8; Plate XIII, Figs. 21, 22. 
Sciurus gilvigularis Waener, Arch. f. Naturg., 1842, ii, p. 43; ibid., 1845, 1, p. 
148; Abhandl. math-phys. Cl. Akad. Miinchen, V, 1850, p. 283. 
Sciurus gilviventris PELZELN (ex Natterer), Verhandl. z.-b. Gesell. Wien, XXXII, 
Beiheft, 1883, p. 59 (Borba, Brazil). is 
Sciurus estuans gilvigularis ALLEN, Bull. Amer. Mus. Nat. Hist., XX, p. 340, 
