182 3. IGUANIDJE 



cc. Throat mottled or with transverse markings, 

 without definite rounded spots. 



U. slevini. p. 194. 



a*. Largest dorsals squamose, usually imbricate, larger 

 than the granular laterals 5 adults less than 75 mm. 

 from snout to anus 5 often a blackish blotch in front 

 of shoulder or a blue blotch behind axilla, 

 bb. A longitudinal dorsolateral line or dermal fold, 

 usually with some enlarged scales on it; usually a 

 second, lateral fold ; no small, rounded blue blotch 

 behind axilla . (Subgenus Urosaurus). 

 ccc. Dorsal scales of one to three (usually two) 

 median longitudinal rows much smaller than 

 those of one to three rows just external to them. 

 d. Dorsolateral fold or line with very large, 

 closely set enlarged scales or tubercles; tail 

 twice length of head and body. 

 About two rows of single, strongly keeled, 

 enlarged dorsal scales on each side of the 

 smaller mid-dorsal series. Clarion Island. 

 U. clarionensis. p. 196. 



d*. Dorsolateral fold or line without enlarged 

 scales or tubercles, or with enlarged scales or 

 tubercles at considerable intervals. 

 e. Thighs without keeled scales; larger, adults 

 usually exceeding sixty millimeters from 

 snout to anus. Socorro Island. 



U. auriculata. p. 197. 



e*. Thighs with keeled scales; smaller, adults 

 usually less than sixty millimeters from 

 snout to anus. 



f . Series of enlarged dorsal scales usually be- 

 ginning in front of a line connecting inser- 

 tions of fore-limbs; dorsolateral tubercles 



