ae 
SCIURUS. 93 
among individuals that frequently makes it so difficult to correctly 
determine a species, and any one who relies upon these numerous 
hues to discriminate what species are before him, will probably, at a 
later period, in the discovery of the blunders that have been made, 
become a wiser and a sadder man. It will doubtless be a long time 
before. the exact status of our American squirrels is satisfactorily 
ascertained. Melanism is of frequent occurrence among _ these 
animals, and erythrism also; the latter perhaps less often; and 
albinism is the rarest of all. Yet in spite of the endless variation in 
colors, and the great difference frequently observed in the size of 
species, as well as occasionally in their form, few would fail to recog- 
nize at once any of these sprightly creatures as not rightfully belong- 
ing to the family Sc1uRID&. 
The remaining genera contain those species familiarly known as 
Gray Squirrels and their allies, although many of them have by no 
means a gray pelage. In size, also, these graceful creatures are very 
variable, and range from the little Bornean species S. soricinus, no 
larger than a mouse, to the great Malayan long-tailed forms almost 
as big as a cat. These last are placed in the genus Katuja. As arule, 
squirrels have no especial nuptial dress, as birds have, but retain their 
individual coloring throughout the year, the completed moult bring- 
ing no change. But one exception to this is known, the S. caniceps 
of India (northern Tenasserim), which assumes on the upper parts in 
winter a bright orange hue, a dress strikingly different from the 
ordinary gray or olive livery worn at other seasons of the year. Of 
the countries embraced in this volume Mexico contains the greatest 
number of these beautiful animals, astonishingly varied in the hues 
and patterns of their coats, making accurate determination of their 
specific relationship a matter at times of considerable difficulty, as 
individuals of the same species, not infrequently, have a totally 
different coloration. 
34. Sciurus. Tree Squirrels. 
Sciurus Linn., Sys. Nat., 1, 1758, p. 63. 
Guerlinguetus Gray, Lond. Med. Repos., xv, 1821, p. 304. 
Macroxus F. Cuv., Dent’s des Mamm., 1823, p. 162. Jd. Dict. 
Cigcc ist vat... x, 1920, p.16. Jd. Dict... Scien: Nat., Lix, 
£8203). 474. 
Rhetthrosciurus (sic) Gray, Ann. Mag. Nat. Hist., 3d Ser., xx, 
COOY. .. 27:2, 
Rhinosciurus Gray, List Spec. Mamm. Brit. Mus., 1843, pp. xxv, 
195, ArinMag. Nat. Hist., 3d Ser., xx, 1867, p. 286. 
Neoscturus Treuss., Le Nat., 11, 1880, p. 292. 
