294 U. 8. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
brown, darker anteriorly, and on the thighs melting into the chestnut described. The whole 
under parts, with the upper lip, are pure white to the roots of the hair. The internal surface 
of the ears is grayish white, except on the anterior margin, which, with the external portion, 
are like the adjacent region. There is a downy white spot at the base of the ears postero- 
internally. 
The prevailing colors of the upper surface of the tail are grayish white and black; of the 
under surface a uniform light yellowish brown, (darker at the end of the tail,) bordered and 
tipped, first with black and then grayish white. On flattening the tail above there is seen, 
first a narrow black line on either side of the skin covering the vertebree, then a broader one of 
quite light yellowish brown, then another of black, of nearly equal width, and, finally, a 
margin of grayish white ; towards the tip the subterminal black increases in extent. 
The specimen described was a female, with the mammae much developed. Of these there 
are four pairs: two in the groin, one on the sides, and one behind the axillae. Those on the 
same side are situated a little closer and closer to each other from before backwards. 
The cheek pouches are very large and extend back as far as the shoulder. The opening is 
wide and situated along the anterior edge of the buccal muscle. The pouches consist of a very 
thin naked sac, separating the skin from the muscles of the jaws and firmly attached to both ; 
their opening is anterior to the teeth in either jaw. 
Fresh measurements of No. 842. 
a — a —+ 
Inches. Lines. || Inches. Lines. 
Nose to.occiput—--Hn5 coc. eens a aao 1 9 Bar width. oat ampind oie a || ee ie 5h 
CAD S SEER SSS sone aean Peaseocsss 8 Arm, from elbows to end of claws-- 1 8} 
CELE wo cena cle Samia ne 1 5 forefoot to end of claws-}--..------ 10 
TOOMOMUL soe see ae ane 5 6 longest toe and claw--..----|--~------- 6 
end of outstretched hind legs 7 1l lonpesti claw 2a 2s Seon |S aeeee ee 2 
Tail, from root to end of vertebra- 3 8 Leg, from knee joint to end of claws-_ 2 6 
hairs--.- t Us hibig2Sees— estes eee 1 4 
Ear, height posteriorly...--------|---------- 8 hind foot from heel to end of 
anieniorly = Seema see see a= ee 6 (ES tee eee ee See il 4} 
internally above skull-| ~-.------- 54 longeste Claw enone ee a tees 2 
above; Doth -eec eee |e een ae 84 longest toe and claw-.-...-..-|-...--.--- 6} 
—E—E————— EE ee eesos — _——————————— 
This species preserves quite a remarkable constancy of character throughout, but little varia- 
tion being discernible in a large number of specimens. One (1559) from Essex county is con- 
siderably grayer, and the black lines of the back have no brownish margin. In a specimen 
from Washington the chestnut tints are darker than described above. I am told that entirely 
black varieties are occasionally met with. In the case of the Siberian ground squirrel there 
appears to be a permanently black variety, known as Zamias uthensis. 
A simple comparison of skins of the European and American striped squirrels, which I have 
recently been enabled to make, is sufficient to show the radical difference between the two. The 
former is the larger animal; the tail is longer, considerably more bushy, and cylindrical. 
