246 IGUANID. 
outwards. A series of very large projecting scales below the lower 
labials ; gular scales keeled, with a longitudinal series of enlarged 
pointed ones on each side; two or three groups of spines on each 
side of the neck; gular folds several, irregular. Back with very 
large erect spinose tubercles, the largest of which form a series ot 
three or four on each side of the vertebral line; two lateral series 
of spines, upper largest ; pectoral and ventral scales more or less 
distinctly keeled. Femoral pores four to twelve on each side, not 
extending on the preanal region, sometimes very indistinct. No 
enlarged postanal scales. Tail once and a half to twice and a half 
as long as head and body. Greyish or brownish above, with a more 
or less marked light dorsal streak and dark brown spots at the base 
of the larger dorsal spines ; a large dark brown spot on each side of 
the nape; two cross streaks between the supraciliary ridges, a band 
from the eye to the angle of the mouth, and another from the eye to 
the middle temporal spine, dark brown; lower surfaces yellowish, 
uniform or with a few small brownish spots. 
millim. millim. 
Total length ...... 125 Fore limb ........ 47 
PNG ad, e4 sca acaga etree 21 Hind limb..... .. 59 
Width of head .... 21 Daal ep acma'e arg alesis 40 
Body: gcisie seacie mers 64 
United States; Northern Mexico. 
a, 9 Tllinois. G. B. Salmon, Esq. [P.]: 
aS. Arkansas, Dr. Macauley [P.]. 
e. Q. Kansas, 
d. 2, Texas, Edw. Cross, Esq. [P.]. 
e. Several sp.: g, Texas. 
Q,& her. 
f-g. Q. N. America. Lord Ampthill [P.}. 
h-t,k. 2 & her. —-? 
1. Ad., stuffed. Mexico. 
m,n. Ad., skeletons. N, America. 
Var. planiceps. 
Phrynosoma planiceps, Hallow. Proc. Ac. Philad, 1852, p. 178, and 
in Sitgr. Exped. Zuni § Color. Riv, p. 124, pl. vii.; Bocourt, J. c. 
p. 238, pl. xii. fig. 11; Yarrow, in Wheeler's Report Explor. W. 
100th Mer. p. 579, pl. xxiv. fig, 1 
Hardly distinguishable from P. cornutum. Ventral and gular 
scales smooth. 
Texas to Sonora. 
8. Phrynosoma maccallii. 
Anota m’callii, Hallow. Proc. Ac. Philad. 1852, p. 182, and in Sitgr, 
rae eel Color, Riv. p. 127, pl. x.; Bocourt, Miss. Sc, Mex., 
