374 U. Ss. P. R. R. EXP, AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
preceding specimens, except that the main furrow is more in the centre, and the portion on 
either side more nearly equal, including that covered and separated by the inner groove. The 
clor is also quite different, being everywhere of a uniform and rather bright reddish brown, a 
little paler beneath. There is no darker wash along the back, where the hairs are very slightly 
darker at the points, only appreciable on close examination. These are everywhere plumbeous 
at base, in marked contrast to their extremities. The feet, tail, and inside of cheek pouches, 
are obscurely whitish. 
Among the specimens before me are three from Morgan -county, Illinois, which exhibit a 
coloration assigned by Audubon and Bachman to a particular season of the G. bursarius. In 
these, the body is of a dark plumbago color, deepest and very lustrous along the centre of the 
back. Beneath, the plumbeous hairs are tipped with yellowish gray; above, their extremities 
are only a little darker. The hands and posterior portion of the arm are clear white, in strong 
contrast to the surrounding fur. The bottom of the cheek pouches is also whitish. The tail 
whitish, except the basal half above, which is plumbeous. 
The tail itself is long and well clothed with hair. The proportions of the limbs are not 
materially different from what has been described in G. bursarius from St. Louis. They may 
be a little smaller. The skull presents some differences : in a more deeply-grooved incisor ; the 
centre of this groove a little nearer the inner edge; a more slender zygomatic arch, the edges 
of the zygomatic process of the upper maxillary being parallel, as viewed from above, instead of 
widening considerably to embrace the end of the malar. The molar teeth are rather broader, 
and the posterior lower one is nearly as wide as the one next to it. There is also a greater 
dissimilarity between the two lobes of the anterior upper molar. The incisors are decidedly 
thicker and more massive. If these differences are constant in many specimens, there will be 
no danger in separating the lead-colored ones as distinct. 
Measurements. 
Red—Iowa. 1882, Black—Mor- 614, Black—Illinois. | 357, Red—St. Louis. 
gan co., Illinois. 
Inches and} Lines. | |Inchesand| Lines. | Inches saat Lines. Length. | ‘Inches and | Lines. 
100ths, 100ths, 100ths. | 100ths. 
NORE LO O00 OL tall see ae oe eee LU of hy aes, he TOMS eee a 8 (iad es 8 > faye ss 
Tail, from root to end of vertebra ~--------- | 2 6 3 2 2 8. Jaeseee 3 Segoe 
portion covered with short hairs. .----- ye) ULE} Ce ere | 2 Guniteazee 2 8 
Arm, fore foot to end of claws ------------- 1 (P 1 8 1 ee ees ae | 1 7 
longest claw ------ 2 Seaee eae ee |-------- | eee + heen RAs ee Pe ees | eee ac 9 
Hand, without claw ...2--.--------------- Te |e eco | a 8 dies, Mea. a” | hoes 
third finger without claw-------.----|-------- 4 |--------|------||-------- Meads «| SSoeas |= 2 epee 5 
Becond ClAW- 2624-206 me eane conan ase ah tena A eat | ert tense = eee Wn Peres 5 ene - = 4h 
lip fin per 2 oo eee tee 2 eee eee eer | tere = |e el ee {a djnok 13 
fonrinvclanys=— 2-236 ole See Se eee ae 7 | aes Sach) See See eee 1). WiGaed) sees |n------- 63 
its finger, (between third) -)-...---- ye F || Seas a | ees eee eee | sv ecaee 1h 
Leg, hind foot from heel to end of claws-.--| 1 | 5 t's Ty lane ote 1 4} 
longest/claw, (second)< <5 <--- cu <cos|cee acces 2 Third ~~ 3 Thirdae! | /2¢ een san) | eee eee 3 
Skull, Jéngthieeremeeeeetet acestes os. Seals. usw. cee esos eee ls Cut Wo VHRR, Ms ae } 20400 Soeeeaee 
WIC R Gaeta aim cele oP 2 rane eee Wa0Bi) (aPoees 169./||)" 1, 28, spears 
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