122 GLIRES. 
Sciurus volucella, Pallas, Nov. Sp. Glir. p. 851 (1778, descr. orig.)*. 
Pteromys volucella, Baird, Mamm. N. Am. p. 286°; Tomes, P. Z.S. 1861, p. 281%, 
Sciuropterus volucella, Allen, Mon. N.-Amer. Rodent. p. 655”. 
Quimichpatlan seu Mus volans, Hernandez, De Quad. Nov. Hisp. fol. 9, cap. xxvi. 
Hab. Norta America, from Labrador® Mexico (Hernandez) ; GuaTEMALA (Salvin*). 
The difference of opinion as to the specific identity of the North-American Flying- 
Squirrels has been already discussed. If the southern form is regarded as distinct, it 
may be considered to range from about 49° North latitude through the United States 
southwards to Mexico and Guatemala. In the former of these last countries it was 
long ago described by Hernandez; in the latter it was discovered by Mr. Salvin*. 
The habits of this species have been well described by various American naturalists, 
most fully, perhaps, by Audubon and Bachman, from their own observations and from 
those of Dr. Smith of Baltimore. It is a crepuscular and gregarious animal; and of a 
summer evening scores may be seen at a time, climbing nimbly to the summit of 
a tree, and then sailing down to the foot of another, apparently in sport. They 
do not build nests in the branches like the true Squirrels, the young, three to six 
in number, being born in a hollow tree. 
2. SCIURUS. 
Sciurus, Linneus, Syst. Nat. i. p. 86 (1766). 
The very natural and almost cosmopolitan genus of true Squirrels is characterized by 
a slender form, well suited for arboreal habits, by a long and often bushy tail, and by the 
absence of internal cheek-pouches and of a flying-expansion of the skin. It is hardly 
less distinguished by the extreme variability in coloration which is found among its 
members, and it has consequently proved a perfect mine of wealth to the species- 
makers. 
More than twenty years ago Professor Baird demonstrated the polymorphism of some 
of the North-American Squirrels*; but it is only lately that similar critical attention has 
been given to those of the Neotropical Region. Of these jifty-nine nominal species 
have been described, no fewer than nineteen having been added to the list in 1867 by the 
late Dr. Grayf. In 1877 Mr. J. A. Allen cleared away much of this confusion t, and 
greatly reduced the number of valid species. Not having access, however, to the 
European museums, he was misled in some cases by the often totally inadequate or 
Sciurus hypochondrus proliais volitans of the ‘Fauna Suecica.’ As these animals were found to be both 
members of the Linnean genus Sciwrus, the name volans was very properly restricted by Pallas and Gmelin to 
the Palearctic species, which now stands as Sciwropterus volans (Linnzus). 
* Mamm. N. Amer. pp. 244, 245. Tt Ann. & Mag. Nat. Hist. 3rd ser. xx. pp. 415-434. 
+ Mon. N.-Amer. Rodent. pp. 666-779. 
