SCIURUS. 123 
even erroneous descriptions of some previous writers; and after an examination of the 
types of no less than forty-nine nominal species, I was enabled in 1878 to throw some 
further light on the subject*, as well as to confirm several of Mr. Allen’s identifica- 
tions ; and most of my rectifications have since been frankly accepted by that gentle- 
man‘. I was then only able to recognize twelve valid species of Neotropical Squirrels, 
of which nine have been received from Central America, three appearing to be peculiar 
to our subregion. This proportion shows that in the New World Sczurus is an essentially 
Nearctic type. Arrived in the tropics, it has developed an endless series of varieties and 
a considerable number of species; but very few new forms are found when we penetrate 
further into the South-American continent. 
The following are the best characters which I can find for the nine Central-American 
Squirrels which appear to be specifically separable :— 
1. S. carolinensis. Average length of head and body 10"; of tail-vertebree about 
8”. Upper parts grey or brownish grey, the middle of the back brownish, a 
rufous lateral stripe usually present; lower parts white. Tail moderate, 
washed with white, the hairs yellowish brown or whitish, with narrow black 
rings, broader black subterminal bands, and white tips. 
2. S. arizonensis. Average length about 12’-50, of tail about 11". Upper parts 
grey, more or less mixed with yellowish brown, especially along the middle 
of the back ; lower parts pure white. Tail long, very bushy, strongly washed 
with white, the hairs tawny or fulvous, each with two narrow and one broader 
black band and a long white tip. , 
3. 8. griseoflavus. Average length (in skin) about 13”:50, of tail 1025. Upper 
parts nearly uniform yellowish grey, the narrow black rings and minute 
whitish tips of the hairs merely obscuring the general tint produced by their 
broad pale-brown median bands. Lower parts yellowish red, the hairs in 
one specimen obscurely ringed with black. Tail bushy, strongly washed 
with white; the hairs yellowish or pale brown, each with two or three 
narrow and one broader black band succeeded by a long white tip. 
4. 8. variegatus. Average length about 10°50, of tail 8°75. Pelage somewhat 
soft, with a good deal of under-fur. Upper parts grey or reddish grey, the 
hairs black, tipped or ringed and tipped with white or red. Lower parts 
deep red, orange, or white. Tail black, washed with white, the hairs usually 
rufous at their bases, with black rings and white tips. 
5. S. hypopyrrhus. Average length about 11-75, of tail 10”. Pelage close-lying 
and rather glossy, with little under-fur. Upper parts dark brown or black, 
often broadly ringed with rufous or white. Lower parts varying from deep 
* «On the Squirrels of the Neotropical Region,” P.Z.S. 1878, pp. 656-670 ; Supplementary Note, tom. 
cit. p. 954. + Bull. U.S. Geol. Surv. iv. pp. 877-887. 
R2 
