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1911] Bryant: Horned Lizards of California and Nevada 
(pin. for.) is at the coronal suture. The two occipital horns 
(occ. h.) are long, smooth, and conical with a small tuberosity 
at the base of each. They are closely set together, an interoccip- 
ital being absent. The postorbitals (postorb.) meet the parietal, 
entirely closing the supratemporal opening. On each of the 
supratemporal (supratemp.) elements are two sharp, recurved 
horns with a third smaller anterior one. The marked upward 
curvature of the temporal horns is a characteristic of this species 
only. The posterior temporal horns are sharp and about equal 
in length. Each jugal (jug.) presents three tuberosities. The 
oecipital condyle is trilobate in shape. The quadrates are small 
and narrow. The vomers slant back and up and are separated 
for over half their length by a wide hiatus. The processes from 
the basipterygoids are slender. The short epipterygoids fit into 
depressions on the petrosal. 
Meckel’s groove is long and narrow. Each angular presents 
three, almost equal sized, conical spines and each dentary (dent.) 
three, the two anterior of which are rudimentary. The artic- 
ulars project downward and are not ossified to the surangulars. 
The supporting of the spiny scales on the mandibles by bony 
tuberosities is peculiar to this species and to Phrynosoma platy- 
rhinos. In this character we find a fine example of a purely 
dermal structure becoming more deep-seated and a bony support 
being developed. In P. d. douglassi and P. b. blainviller no 
spinose ossifications are to be found on the lower mandible. 
However, well-developed spinose scales are present. In P. platy- 
rhinos and A. maccalli the seales present the same appearance 
exteriorly, but are supported by a bony spine. The same can 
be noted on the jugal and supraorbital regions (pl. 2). There 
is, therefore, a growing tendency in some species to support the 
dermal scales by bony spines. That the occipital spines were 
developed by the same stages seems probable. The bony spines 
appear to be simply processes from the bone itself and not small 
ossifications inside the scale which secondarily fuse with the bone. 
The orbital opening (orb.) is oval in shape. The supratem- 
poral openings are completely roofed with bone by the meeting 
of the parietal (par.), supratemporal (supratemp.), and post- 
