666 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
TABLE V.—List of specimens examined of SCIUROPTERUS VOLUCELLA var. VOLUCELLA—Continued, 
| 
| 
oe : T - - 
ae | ee 
3 a | 5 
a [eg] S|] | Ey 
5 Se = f When From whom re- ie | a = 
a Est] 2 ep Locality. : Collected by — oe, Remarks. 
Ve 5 = collected. ceived. ° 
=i Sell ey 2 | 
Fale e| 3 |e 2 
[S@/E 2) & |p 3 
2oam/k 2 = = 
é°|8" | 8 |¢ . | 2 
FBG) |\.32204[beee =: eee | Columbus, Miss ...|......-..--- Dr. Spillman ....} Dr. Spillman ....) Skin ...... | In Nat. Museum. 
TET Gecsec| reece ePecthie any hoa senegen bastocSsa se eet OOl.a-e eee eee OO ie. vacates eC ease .--. do. 
PARP eee eats .---| Prairie Mer Rouge, |..-..--..--- J. Fairio --...--. J. Fairie ......- PeU Wi gaaeee pee Oy 
La. 5 
AQIS || Saco Sasa |.-..| New Orleans, La..|......:..-- J. Varden.....-- J. Varden....... | Alcoholic .|....do. 
7361 |e |-=-===|=-0-|| Grand Coteau, Jum, |.---.--.--- St. Charles:Col- |.....-....-...-.-- ee sQ0 2.22.22 ...-do. 
| | lege. 
Genus SCIURUS Linneeus. 
Sciurus LINN ACS, Syst. Nat. 10th ed. 1758 (in part), and of most subsequent authors. 
Macroxus ¥. Cuvier, “ Diet. des Sci. Nat. x, 1818” *; Mém. du Mus. x, 1825, 122; Dents des Mam. 1825, 
161; Diet. des Sci. Nat. lix, 1829, 474. (Type Seiurus estuans Linn.) 
Macroxus Gray, Ann, & Mag. Nat. Hist. 3d ser. xx, 1857, 275. (Not Macrorus F. Cuvier.) 
thinosciurus GRAY, Cat. Mam. Brit. Mas. 1843, 195; Ann. & Mag. Nat. Hist. 3d ser. xx, 1867, 286. (Type 
Sciurus tupaoides Blyth.) 
Theithrosciurus Gray, Aun. & Mag. Nat. Hist. 3d ser. xx, 1867, 272. (Type Sciurus macrotis Gray.) 
Generic Cuars.—Skull short, very broad, especially interorbitally, and the 
cranial portion greatly expanded ; postorbital processes terminating in a long, 
slender point, directed posteriorly (and more or less outwardly) and decurved; 
malar bone slender, the plane of its expansion nearly vertical ; anteorbital 
foramen a narrow vertical slit, opening far in advance of the first premolar ; 
upper grinding-teeth four or five, the first premolar (when two are present) 
very small; muzzle short, nasals greatly narrowed posteriorly; ears well devel- 
oped, well clothed, sometimes tufted, especially in winter; tail long, generally 
as long as or longer than the body, broad, the long hairs spreading laterally; 
nail of pollex rudimentary; pelage generally full and soft, but sometimes 
more or less rigid; coloration variable, but never with well-defined black 
stripes on the dorsum; size generally large; no cheek-pouches, and no lateral 
membrane connecting the fore and hind limbs. 
The true arboreal Squirrels are at once easily distinguishable from the 
Flying Squirrels by the absence of the membranous expansion along the 
sides of the body as well as by numerous other very obvious differences. 
They differ from Tamias in the form and position of the anteorbital foramina, 
the broader and less tapering muzzle; in the greater verticality of the plane 
of the malar bone; in the greater convexity of the dorsal outline of the skull; 
“See Agassiz, Nomenclator Zoologicus, Mamm. p. 19. 
