20-1 IGUANID^. 



millim. millim. 



Total length 302 306 



Head 31 27 



Width of head 27 22 



Body 76 73 



Fore limb 44 41 



Hind limb 90 82 



TaU 195 206 



Southern and Central United States ; North Mexico. 



a-e. cJ $ . N. Texas. E. D. Cope, Esq. [E.]. 



/. (5 • Creek Boundary. 



ff. 2 ■ Colorado. W. Treharne, Esq. [P.]. 



2. Crotaphjrtus wislezenii. 



Crotaphytus wislezenii, Baird fy Gir. Proc. Ac. Philad. 1852, p. 69, 



and in Stcmsbury'' s Exped. Gr. Salt Lake p. 340, pi. iii., a7id U.S. 



Mex. Bound. Surv., jRcpt. p. 7, pi. xxxi. ; Bocourt, Miss. Se. Mex.^ 



Bept. p. 155, pi. xvii. bis. fiof. 4. 



gambelii, Bainl ^- Gir. Proc. Ac. Philad. 1852, p. 126. 



fasciatus, Hallow. Proc. Ac. Philad. 1852, p. 200, and in Sit- 



f/reave's Exped. Ziini S,- Color. Biv. p. 115, pi. \. 

 Leiosam'us hallowellii, A. Dum. Arch. Mus. viii. p. 533. 



This species differs from C. coUaris in the following points : — 

 Head smaller and narrower ; nostril more lateral : upper head- 

 scales smaller, those bordering the orbit above not differentiated, in 

 three or four longitudinal series on the interorbital region ; a much 

 elongate scute below the orbit. Male with enlarged postanal scales. 

 Coloration very variable ; no black collar. The specimens in the 

 collection are greyish brown above, with large round brown spots 

 and narrow transverse light (vermilion) bands on the back, limbs, 

 and tail ; lower surfaces white, throat spotted or streaked with grey. 



S. 2- 



millim. millim. 



Total length 314 255 



Head 26 26 



Width of head 20 20 



Body 78 79 



Fore limb 43 44 



Hind limb 85 87 



Tail 210 150 



Western North America, from Oregon to North Mexico. 



Smithsonian Institution [P.]. 



