CROCODILIANS, LIZARDS, AND SNAKES. 409 



white; tips of largest cephalic spines marbled w'.th ochei*; underside yellowish 

 white, densely marbled with blackish; collar, light ocher yellow." lu these speci- 

 mens even the gloss of the black lava was imitated. 



PHRYNOSOMA DOUGLASII Bell. 



Phrynosoma douglas'ti \\''aglp:u, Syst. Amph., 1830, p. 116. — Wiegmann, llorpt. 



Mex., 1834, p. 54.— Holuhook, N. Am. Herpet., II, 1842, p. 101, pi. xiv.— 



GiKARi), Stausbury Expl., 1852, p. 362, pi. vii, figs. 6-9.— Copp:, Proc. Acad. 



Nat. Sci. Phila., 1866, p. 302.— OOUES, Wheeler's Report Expl. W. 100th Mer., 



V, 1875, p. 591.— Gkav, Synopsis, Rept. Grifl'.,Cuv. Anim. Kingd., IX, 1831, 



p. 44 ; Cat. Liz., 1845, p. 227 ; Zool. Beechey's Voy ., 1839, p. 96. — DuiMeril and 



BiBRON, Erp. G^n., IV, 1837, p. 323.— Fitzinger, Syst. Rept., 1843, p. 78.— 



BouLENGEK, Cat. Liz. Brit. Mus., 1885, p. 240. 

 Agama douglassii Bell, Trans. Linn. Soc., XVI, 1833, p. 105, pi. x. — Harlan, Med. 



and Phys. Res., p. 141, plate, fig. 3. 

 Phrynosoma orbiculare Hallowell, Sitgreaves Exped. Znui and Colo. River, 1853, 



p. 125, pis. VIII, IX. 

 ^Tapaya hcrnaiidcsii Girard, U. S. Expl. Expd. (Ch. Wilkes), Herp., 1858, p. 395; 



U. S. and Mex. Bound. Survey, 1859, p. 8. — Bocouut, Miss. Sc. Mex., Rept., 



1874, p. 228. 

 Tapaya hnvirostris Giuard, U. S. Expl. Expd. (Ch. Wilkes), Herp., 1858, p. 397.— 



Bocourt, Miss. Sc. Mex., Rept., 1874, p. 229. 

 Tapaya doiujlassii Girard, U. S. Expl. Expd. (Ch. Wilkes), Herp., 1858, p. 397, 



pi. XXI, figs. 1-5.— BocoUKT, Miss. Sc. Mex., Rept., 1874, p. 226, pi. xi, fig. 5. 

 Phrynosoma hrevirostre Cope, I*roc. Acad. Nat. Sci. Phila., 1866, p. 302. 



Outline of head from above, parabolic; profile of muzzle descending 

 steeply and convex to a projecting lip border. Temporal region wide, 

 but not especially expanded. Nostril iu the line of the canthus ros- 

 tralis. Horns represented by conical protuberances on each side. 

 Three temporals and one occipital, of which the occipital is about as 

 prominent as the second temporal and less so than the third temporal. 

 Occipitals widely separated at base. The temporal row of scales is 

 continued to below the orbit, but the latter are not prominent. Scales 

 of vertex convex, rugose; occipital and two posterior to it, with one 

 within and adjoining the posterior superciliary, a little larger than the 

 others. Six posterior inferior labials enlarged, the most posterior with 

 produced angles, forming a series of subrictals. One series of enlarged 

 infralabials, which are not so prominent and do not extend as far pos- 

 teriorly as the subrictals. Two short oblique rows of conic scales on 

 the side of the neck, tlie superior the longer. Two large scales in ver- 

 tical relation behind nasal, and separated from it by a row of smaller 

 scales. A small keystone superciliary. Gular scales rounded, smooth. 



Median dorsal scales flat, keeled, of irregular sizes, but not so large 

 as in the species of the cornntum or coroiKdiim groui)S. Lateral dorsal 

 scales rounded, smaller, but not so small as in the coronatum group. 

 The large isolated keeled scales are less conspicuous than in the other 

 gi'oups and are in about four rows on each side. They are not sur- 

 rounded by a rosette at base. A single series of moderately elongate- 

 closely placed marginal scales, commencing anterior to the groin and 



