86 3. IGUANID.^ 



h\ — Very large; few if any caudals spinose; upper surfaces 

 very coarsely marked or blotched with blackish brown 

 and yellow, orange or red; scales in a caudal whorl not 

 fewer than 63 (63 to 76); ventral rows between 



gular fold and anus 140 to 156. 



S. varius. — p. 101. 

 a'.— Scales in a caudal whorl at largest part of tail not more 

 than 50; nuchal scales strongly spinose, largest larger 

 than largest scales on top of head, almost as large as 

 largest preauriculars; not more than 25 dorsals in a 

 head-length. 

 bb. — Scales on limbs less strongly keeled, often nearly 

 smooth on posterior surface of lower leg (tibia) ; 

 scales much less spinose on limbs and tail ; most dorsal 

 scales not spinose; adults mottled; size moderately 

 large; about 20 to 25 dorsals in a head length. 



S. slevini. — p. 97. 

 bb". — Scales on limbs more strongly keeled; posterior sur- 

 face of lower leg with strongly keeled scales; scales 

 much more spinose on limbs and tail; nearly every 

 dorsal scale ending in a short spine; adults blackish, 

 nearly unicolor; size very large; about 15 to 20 dor- 

 sals in a head length. 



S. hispidus. — p. 99. 



10. Sauromalus ater Dumeril 



Chuckwalla 



Plates 3 and 4 



Sai/romn/us ater Dumeril, Arch. Mus. Hist. Nat. Paris. Vol. VIII, 1856, 

 p. 5 36, pi. XXIII, figs. 3, 3a (type locality, unknown) ; Cope, Bull. 

 U. S. Nat. Mus., No. 1, 1875, p. 47; Bocourt, Miss. Sci. Mex., 

 Kept., 1874, p. 149, pi. XVII bis., fig. 11; Coues, Surv. W. 100th 

 Merid., Vol. V, 1875, p. 600; Yarrow, Bull. U. S. N.it. Mus., 

 No. 24, 1883, p. 51 ; Boulenger, Cat. Lizards Brit. Mus., \'oI. II., 

 1885, p. 202; Cope, Bull. U. S. Nat. Mus., No. 32, 1887, p. 35, 



