11. With four large spines at the back of the head (occipital region) form' 



ing a continuous series with the three large temporal spines on each 

 side 



Phrynosoma solare Gray Regal Horned Lizard 

 (Phrynosoma regale (Girard) ) 

 With two occipital spines at the back of the head between the temporal 

 spines 12. 



12. Chin with three or four rows of enlarged scales on each side (of mid' 



line, within the row of spines on the angle of the lower jaw) 13. 



Chin evenly scaled or with one row of enlarged scales so situated 14. 



13. Scales on top of the head between the eyes smooth; S. Cal. 



Phrynosoma hlainvillii blainvillii (Gray) San Diego Horned 



Lizard 

 (Phrynosoma coronatum hlamvillii (Gray) ) 

 Scales on top of the head between the eyes rough or striated; Cal. 

 Phrynosoma hlainvUhi frontale (Van Denburgh) California 



Horned Lizard 

 (Phrynosoma coronatum frontale (Van Denburgh) ) 



14. With two rows of enlarged scales or spines along each side; head spines 



rather long 15. 



With one row of spines along each side; head spines moderate to short 16. 



15. Tympanum exposed; with a light mid'dorsal line; Colo, to Ark. and 



Ariz., and southwards into Mexico 



Phrynosoma cornutum (Harlan) Texas Horned Lizard 

 Tympanum covered by scales; with a dark mid-dorsal line; Ariz, and 

 Cal. 



Phrynosoma m'callii (Hallowell) MacCalFs Horned Lizard 



16. With a single large temporal spine on each side of and evenly spaced 



with the two occipital spines (in the middle of the back of the head) ; 

 chin shields (on angle of lower jaw) conspicuous and larger posterior' 

 ly; Wash, and Idaho to Ariz, and Cal. 



Phrynosoma platyrhmos platyrhinos Girard Smooth Horned 

 Lizard 

 With three short temporal spines grouped on each side of the two OC' 

 cipital spines, which are short and stubby and widely separate; chin 

 shields mostly uniformly small; Wash, to Cal. and Texas 



Phrynosoma orbiculare Wiegmann Douglass's Horned Lizard 

 (Phrynosoma douglassii (Bell) ) 

 (Several intergrading subspecies) 



17. Ear opening hidden; limbs very small; with one digit on each fore limb 



and two on each hind limb; Florida 



J\leoseps reynoldsi Stejneger TwO'toed Lizard 

 (of Family Scincidae) 

 Not so 18. 



18. With a large fold of skin, lengthwise along each side, closely folded to 



the body; back with large squarish scales; Family Anguidae Plated 

 Lizards 19, 



366 



