MAMMALIA. 193 
f6l.] 1. Preromys Sasrinus. Severn River Flying Squirrel. 
Genus Pteromys. Cuvier. Sciuropterus. F. Cuvier. 
Greater Flying-Squirrel. Forster, Phil. Trans., vol. lxii. p. 379- 
Severn-River Squirrel. Pennant, Hist. Quad., vol. ii. p. 153. Arct. Zool., vol. i. p. 122. 
Sciurus Hudsonius. GMELIN, Syst., vol. i. p. 153. 
Sciurus Sabrinus. SHaw, Zool., vol. ii. pt. i. p. 157. 
Pteromys Sabrinus. RicuarDson, Zool. Journ., No. 12. p.519, April, 1828. 
Pt. (Subrinus), super ex rubescenti brunneus, cauda planiuscula corpus subequanti dorsoque concolori, lobulo 
membrane volitantis rotundato. 
Severn River Flying-squirrel, pale reddish-brown above ; tail flattish, nearly as long as the body, and of the 
same colour with the back ; flying membrane having a small rounded projection behind the wrist. 
This is a very distinct species from the much smaller Assapan, (Pé. volucedla) 
which is common in the United States. It was first described by Forster, who saw 
a specimen brought from Severn River that falls into James’s Bay, and was con- 
sidered by him to be the same species with the European flying squirrel, which 
it much resembles. I have followed Pennant and Shaw in separating it from 
the latter, on account of its longer tail, different coloured fur, and the smallness 
of the rounded projection of the flying-membrane behind the wrist. 
The Severn River Flying Squirrel does not extend its range further north than 
latitude 52° (unless the Rocky Mountain one prove to be only a variety of it.) 
Mr. Tod sent me a specimen from Penetanguishene on Lake Huron, and I have 
seen others from Moose Factory, at the bottom of James’s Bay. 
DESCRIPTION. 
Dental formula, incisors £, canines =, grinders 3 = 22. 
Head round, nose short and obtuse, covered above with a smooth shining coat of light 
gray hair. Incisors nearly even with the end of the nose, anteriorly of a deep orange colour. 
Whiskers black, longer than the head. yes large, surrounded by a blackish-gray marking 
in the fur. Flying-membrane extending from the wrist to the middle of the hind leg, nearly 
straight, having only a very slight rounded projection close to the wrist. 
The fur is every where remarkably fine and soft. On the dorsal aspect of the head, body, 
and flying-membrane, it is of a deep blackish-gray colour from its roots to its tips, which are 
of a pale reddish-brown, and which form the colour of the surface when the fur lies smoothly. 
There is no different coloured stripe on the flying-membrane, but the dark colour of tlie 
roots of the fur is more easily seen there. The outer surfaces of the fore and hind-feet are 
2C 
