366 3. ICUANIDM 



it showed signs of renewed energy and was ready to run at 

 anyone's approach." 



Synopsis of Species and Subspecies 

 a. — Nostrils opening on or almost on the lines joining the 

 supraorbital ridges with the end of the snout, 

 b. — Gular scales small, nearly equal-sized or with one 

 row on each side enlarged} a series of enlarged 

 scales below, but not very much larger than, the 

 lower labials J occipital spines very short or absent} 

 peripheral fringe of one series of spinose scales. 

 c. — Ventral scales smooth} no prominent ridge from 

 tip of postorbital boss to outer enlarged temporals} 

 lower jaw not enormously developed posteriorly} 

 one to three rows of smooth scales between infrala- 

 bials and enlarged sublabials, 

 d. — Head-spines smaller} cccipitals usually nearly 

 erect. 

 e. — Size smaller; head spines very rudimentary} 

 temporal spines erect like occipitals, not pointing 

 posteriorly. p_ ^_ douglassii.-p. 368. 



e'. — Size larger} head spines a little larger} temporal 

 spines less erect, not parallel to occipitals. 



P. d. ornatissimum. — p. 377. 

 d'. — Head-spines larger; occipitals usually directed 

 backward, nearly parallel with temporals} tem- 

 poral spines often reddish. 



P. d. hernandesi. — p. 3 82. 

 c'. — Ventral scales strongly keeled} a prominent ridge 

 from tip of postorbital boss to outer enlarged tem- 

 porals; lower jaw enormously enlarged posteriorly; 

 five to seven rows of keeled scales between infra- 

 labials and enlarged sublabials. 



P. ditmarsi. — p. 386. 



