392 U. Ss. P. R. R. EXP. AND. SURVEYS—ZOOLOGY—GENERAL REPORT. 
List of specimens. 
- Measurements. 
a ee : 7 2 lf#lelala ies 
E 3 : Locality. Whence and how 2 Nature of} melee Dis hace bese es Fi Sh lee S By 3 
E Zz & obtained. = |specimen. = | 3 = £ iS 2. = S |= E z 
2] e | = eis loa | o | Biel eis | sso eanomed 
2| 8 | & ojeete | o |S beaeue eq eee 
g E |x a a 2 a z = |/s|'2 de i 
&§ | 35 |e 5 z\ez |2|2 | 8 |81e6)8 lejal|oa Ele 
PATS |ccoses +«--| Tejon Valley, Cal.) Lt.R.S.Williamson| 2 | Mounted.) ......|.ccece|scsees|eveee lessees ata evcclecee 
sleesees O.. cece veecer|ceee |asGOr. cave svevarleccces| srveslecceeelsevensieves 
Lt.W. P.Trowbridge}....| Skin ....].0. ssjeccees 1.60 | 6.10 | 3.08 
caccecAOQscccccccccceloccs| MOUNtEd.|.s000-|ccnnes eccve:|secccclecsces cocelecccce tees 
evens dO.. seveccceee Ove caer |svcccv|eccsec|eccces|encecelenennslecosiaseoce|cecvaclecss 
A. 8. Taylor In ale yi Me 0 ea enc 50h Aso) CARS Kock [b.3 
eecens do. ..d0... . ensecaleeansa}escess| 2208 1,00 | 1.14 
elecvecs do. a -O.. 000 87 | 1.50 | 1.70 | 5.70 | 2.27 80 | 1.00 
William Hutton....]....] Skull. ..|...ses|eeeees encne|cevcec|scvceelnoce|scccas|evece |s eee 
A. J. Grayson...... -eee| Inalc....| .90| 1.52 | 2.05 | 5.85 | 2.70 |....| 1.13 | 1.20 
PEON oneaesl|anen|lonencle GO. scccaccisecnlec veesOOs. cans coverslcece|..UQacves -85 | 1.50 | 1.90 | 5.46 | 2.50 |....] .95 | 1.04 
ii 
1. 
2 Collected by Dr. Heermann. 
THOMOMYS LATICEPS, Baird. 
Broad-headed Gopher, 
Thomomys laticeps, Barry, Pr. A. N. Sc. Phil. VII, April, 1855, 335. (Humboldt Bay.) 
Sp. Co.—Cheek pouches moderate, well haired. Tail nearly one-half the body, thick at base. Skull very broad and 
muzzle short ; the upper incisors convex, the groove quite distinct. Feet very large and broad. Claws of fore foot or 
hand small, slender, 4 lines long above; below, about two-sevenths the length of the whole hand, its digit about two- 
eighths. Claw of thumb extending over nearly three-sixths the hand. 
Color.—Above, yellow reddish brown; the dorsal region with the hairs largely and sharply tipped with blackish; sides 
nearly uniform ; beneath, tinged with reddish. Pouches dull white, the dusky of the surrounding region dipping into 
them. Tail grayish white, dusky above. / 
This species, with one from the upper Missouri, is eminently characterized among all those 
with smooth upper incisors by the very broad and powerful feet and larger hands. The ear 
flap is short though distinct ; the whiskers short and of a grayish color. The fur is soft, silky, 
and moderately long. The tail is much developed, very thick at the base, and almost half the 
length of the body, well coated with hair. The pouches are not very large, densely furred 
inside next the head, more sparsely elsewhere. 
The fore fect are large, especially the palms; the first finger or thumb is short, though 
inserted quite far forwards its claw does not quite reach to the middle of the hand, (from wrist 
to point of claw.) The claws generally are rather small, much curved, and quite slender ; the 
third projects, on its lower edge, to a distance which is contained about three and a half times 
in the entire hand, or }ths; its phalanges only about half the length of the palm proper. 
The second finger and claw are considerably longer than the fourth ; the point of the fifth claw 
extending more than half the total length of the hand; the first claw extending as far as the 
