56 University of California Publications in Zoology [Vou.9 
postanal plates. See table of measurements for dimensions and 
proportions of the lizard. 
The ground color is usually ashy gray or yellowish. Two 
rows of round, dark brown spots containing a paler center, cen- 
tered with a brown dot, are arranged on either side of the median 
line (pl. 7, fig. 15). The neck patches are pale and inconspic- 
uous. A narrow brownish median line leads from the occiput 
to the tail. Ventrally the color is silvery or yellowish white 
(pl. 7, fig. 16). The head is unspotted and the horns but little 
darker in color. Although this description of the coloration will 
fit many specimens, yet it is by no means the only type, for there 
are great variations in color. For general color pattern see plate 
7, figure 15. 
OSTEOLOGY 
Diagnostic Characters—Horns of occipital region long, 
smooth, and conical; interoccipital horn lacking; supratemporal 
horns three in number on each element, the posterior two sharp 
and of about equal length; jugal with three tuberosities on a 
line above the row of supratemporals; superciliary processes 
from premaxillaries twice as long as those from frontal; parietal 
region dome-shaped; postorbitals meeting parietal and supra- 
temporals, thus closing the supratemporal opening; quadrates 
short (4mm. in length) and narrow; lower mandible with six 
spinose tuberosities on each side, the two anterior ones on each 
side rudimentary; epipterygoids articulating in a depression of 
the petrosal; articulars not ossified to surangulars; all the caudal 
vertebrae with well-developed transverse processes. 
Description—tThe alveolar portion of the premaxillary (pre- 
macx., fig. F) element is very little wider than the element itself 
and does not appreciably border the nasal opening (nas. op.). 
The supramaxillary processes are wide and heavy, and articulate 
with processes from the palatines. The frontal (fron.) shows 
elevations for the enlarged scales bordering the orbit (orb.). 
The prefrontal (prefron.) supereiliary processes are long (3.5 
mm.), arching the orbits for two-thirds of the distance. The 
frontal superciliary processes are short (1-2 mm.). Small post- 
orbital spines are situated at the lateral angles of the frontal. 
The parietal (par.) region is dome-shaped; the pineal foramen 
