6 BULLETIN 1091, U. S. DEPARTMENT OF AGRICULTURE. {b^ILNo?!, 
longer than the body. Cranium triangular, the occiput forming the 
base and the point of the nose the apex of the triangle, much flat- 
tened, auditory and particularly mastoid bullae conspicuously in- 
flated. 
COLOR. 
General color above, brownish buffy. varying in some specimens 
to lighter buffy tints, grizzled with black ; oblique hip stripes white ; 
tail with dark-brown or blackish stripes above and below, running 
into blackish about halfway between base and tip, and with two 
lateral side stripes of white to a point about halfway back; tail 
tipped with pure white for about 40 millimeters (PI. I). Under- 
parts white, hairs white to bases, with some plumbeous and buffy 
hairs about base of tail; fore legs and fore feet white all around; 
hind legs like back, brown above, hairs with gray bases, becoming 
blackish (fuscous-black or chsetura-black) about ankles, hairs on 
under side white to bases; hind feet white above, dark-brown or 
blackish (near fuscous) below. 
Color variations in a series of 12 specimens from the type locality 
and points widely scattered through the range of spectabilis consist 
in minor modifications of the degree of coloration, length of white 
tip of tail, and length of white lateral tail stripes. In general the 
color pattern and characters are remarkably uniform. Young speci- 
mens, while exhibiting the color pattern and general color of adults, 
are conspicuously less brown, and more grayish. 
There appears to be little variation in color with season. In the 
series at hand, most specimens taken during the fall, winter, and 
spring are very slightly browner than those of summer, suggesting 
that the fresh pelage following the fall molt is a little brighter than 
is the pelage after being worn all winter and into the following 
summer. But at most the difference is slight. 
OIL GLAND. 
Upon separating the hairs of the middle region of the back about 
a third of the distance between the ears and the rump, one uncovers 
a prominent gland, elliptical in outline, with long axis longitudinal 
and about 9 millimeters in length. The gland presents a roughened 
and granular appearance, and fewer hairs grow upon it than else- 
where on the back. The hairs in the vicinity are frequently matted, 
as if with a secretion. In worn stage of pelage the gland may be 
visible from above without separating the hairs. Bailey has sug- 
gested that this functions as an oil gland for dressing the fur, and 
our observations bear out this view. Kangaroo rats kept in cap- 
tivity without earth or sand soon come to have a bedraggled ap- 
pearance, as if the pelage were moist. When supplied with fine, 
