1853.] 407 
hairs, more numerous on the head and cheeks; dark plumbeous on the sides and 
belly, the hairs of the first tipt with brown, of the other with grey and light 
brown. Head very moderately blunt; lips white; ears small, rounded, hairy 
both within and without, and concealed under the fur; antitragus large, semicir- 
cular. Feet dusky, covered with short hair; thumb with a compressed, rounded 
nail. ‘Tail above black, beneath dusky, very slightly covered with hair. 
Length 5:2: ; head 1.1.3; ears °125; fore leg -9; hind leg 1-4; tail 1:4. 
Said by Bachman to be the Arv. pinetorum, to which it bears very little re- 
semblance. 
6. ARvicoLa NAsuTUS. Capite satis magno, magis quam in ceteris producto. 
Auribus ovalibus extra pilos exstantibus. Cauda bene vestita, supra fusca, 
subtus cinerascente. 
Hab. Cum priore. A. nasuta Bach., Journ. Acad. Nat. Sci., vol. viii. p. 296. 
A. nasutus Wiegman, Arch. tor 1843, part 2 p. 53. A. noveboracensis Rich., 
l. c. p. 84. A. palustris Harlan, Fauna Americana, p. 136; Schinz. l. ¢. p. 
251. 
Hair dark plumbeous, above about equally tipt with dark and light brown, 
having somewhat of a hirsute appearance, of a uniform mixed color over all the 
upper parts, beneath dark cinereous tipt with grey. Head moderately large, 
more elongated than in others. Ears oval, projecting beyond the fur, hairy both 
within and without; antitragus moderate, semicircular. Feet covered with 
shining, pale brown hair; thumb tubercle, with a compressed, curved, blunt 
nail. Tail well covered with hair, above dark brown, beneath greyish. 
Length 6:5; head 1-8; ears -35; fore leg -8; hind leg 1¢4; tail 1:2. 
I have not, myselr, met with this species any where but in Pennsylvania, but 
I have heard of it in almost all the Northern States. It has been confounded by 
Richardson with the A. noveboracensis of Rafinesque, which it very much re- 
sembles, but is easily told by the longer and narrower head, and by a difference 
in the upper incisors. Dr. Harlan, in his Fauna Americana, wishing to deprive 
Mr. Ord of the merit of having first described the A. riparius, published this 
species under the name of A. palustris, and quoted A. riparius.as a synonym. 
His own ignorance defeated him in this project, and made his ill faith more ap- 
parent. Had he only been honest, he would have consulted Mr. Ord on the 
identity of the two animals, and then might have justly claimed this species as 
his own. 
7. Arvicota Pennsytvanicus. Capitesatis magno et obtuso, dentibus primo- 
ribus superioribus margine interiore leviter subsulcatis. Auribus brevibus sub- 
pilis occultis, antitrago magno, auris aperturam omnino occludente. 
Hab. In provinciis borealibus. (Phila., Mr. Ord.) Arv. pennsylvanicus Ord. 
A. riparius Rich., l.c. p. 120. A. xanthoguathus Dekay, |. c. p. 90. Lem- 
mus noveboracensis Raf. A. pennsylvanicus Wagner, I. c. p. 589; Schinz., 1. 
Ce Ds 247- 
Hair long, soft and glossy, dark lead color, above tipt with brown intermixed 
with longer black hairs, beneath tipt with shining grey. Head moderately blunt 
and large, upper incisors very slightly sulcate on the inner edge; lips white; 
ears oval, projecting a little beyond the fur, hairy both within and without; an- 
titragus large, semicircular, entirely closing the auditory passage; feet dark 
brown, covered with short shining hair; thumb tubercle with a short, com- 
pressed, blunt nail. Tail depressed, well covered with hair, black, beneath a litile 
aler. 
R Length 7 in. ; head le4; ears -25; fore leg -9; hind leg 1:7; tail 1-8. 
The dentition is nearly the same as of the A. riparius. In the upper jaw the 
posterior interior angle is furnished with a small, sharp, posterior lobe, and the 
third molar of the lower jaw terminates in a roundish piece, which is so cut by 
the last re-entering angle on its inner side as to form another interior salient 
angle, whence the interior line of teeth in the lower jaw is composed of 12 salient 
and 11 re-entering angles. 
This species, first described by Mr. Ord, is probably the one poncoumced By 
