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 SCIURID^. 



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. soricimis, 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 Ratufa. As a rule, 

 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 Sqviirrels. 



Sciurus Linn., Sys. Nat., i, 1758, p. 63. 



Guerlinguetus Gray, Lond. Med. Repos., xv, 1821, p. 304. 

 Macroxus F. Cuv., Dent's des Mamm., 1823, p. 162. Id. Diet. 



Class. Hist. Nat., x, 1826, p. 16. Id. Diet. Scien. Nat., LIX, 



1829, p. 474. 

 Rheithrosciurus (sic) Gray, Ann. Mag. Nat. Hist., 3d Ser., xx, 



1867, p. 272. 

 Rhinosciurus Gray, List Spec. Mamm. Brit. Mus., 1843, pp. xxv, 



195, Ann. Mag. Nat. Hist., 3d Ser., xx, 1867, p. 286. 

 Neosciurus Treuss., Le Nat., n, 1880, p. 292. 



