CHECKLIST OF REPTILES OF MEXICO 141 



8. Enlarged dorsals commencing caudad of a line joining the anterior points of 



insertion of the forelimbs; dorsals weakly keeled, rounded posteriorly, 

 prominently pavemented; general habitus not at all rugose .unicus (p. 147) 

 Enlarged dorsals commencing craniad of a line joining the anterior points of 

 insertion of the forelimbs, or else equal with such a line; dorsals prominently 

 keeled, usually mucronate or spinose, imbricate; ventrals imbricate; general 

 appearance rugose 9 



9. Form rugose; enlarged dorsals strongly carinate and prominently mucronate- 



tubercles of lateral and dorsolateral folds well developed; ventrals mucro- 

 nate; gular surface generally stippled, with a light median area; blue ab_ 

 dominal patches of males quite extensive, .bicarinatus bicarinatus (p. 146) 

 General appearance somewhat less rugose; enlarged dorsals not so often 

 mucronate; tubercles smaller, sometimes absent; ventrals less mucronate, 

 occasionally rounded; gular surfaces evenly stippled; abdominal blue of 

 males sometimes restricted to small sternal patches 10 



10. Ventrals rounded; dorsolateral and lateral tubercles very poorly developed; en- 



larged dorsals commencing on the nape bicarinatus nelsoni (p. 147) 



Ventrals submucronate to mucronate; dorsolateral and lateral tubercles well 

 developed; enlarged dorsals commencing on the shoulders just craniad of a 

 line joining the anterior points of insertion of the forelimbs 11 



11. Ventrals mucronate, prominently carinated laterally; gular scales with a 



tendency toward pavementation, especially anteriorly; gular surfaces evenly 

 stippled; abdominal blue of males restricted to small sternal patches. 



bicarinatus anonymorphus (p. 146) 



Ventrals submucronate (occasionally rounded), only faintly keeled on the 



lateral portions of the belly, or else not at all; gular scales imbricate; gular 



region \\'ith an even blue wash, and only barely flecked if at all; abdominal 



blue of males evenly distributed bicarinatus tuberculatus (p. 147) 



12. Enlarged dorsals commencing on nape 13 



Enlarged dorsals commencing on shoulders or caudad of them 14 



13. Enlarged dorsals strongly keeled; scales of primary and secondary series 



almost equal in size; postfemoral dermal pocket absent or rudimentary; no 



prominent lateral pattern of dark whorls clarionensis (p. 142) 



Enlarged dorsals not so rugose, scales of primary series prominently larger 

 than those of the secondary series; postfemoral dermal pocket regularly 

 present; a distinct lateral pattern of dark whorls. omatus schottii (p. 144) 



14. Tail two or more times length of head and body combined. graciosus (p. 144) 

 Tail less than twice length of head and body combined. 15 



15. Enlarged dorsals extending onto basal portion of tail for a distance equal to 



length of femur, or more; entire gular region, including sublabials, a uniform 



bright blue omatus caeruleus (p. 143) 



Enlarged dorsals extending onto basal portion of tail for a distance equal to less 

 than length of femur; entire gular region including sublabials never com- 

 pletely blue 16 



16. Enlarged dorsals often irregularly arranged; lateral tubercles not afifecting 



diagonal arrangements; average size less than 45 mm. from snout to 



vent 17 



Enlarged dorsals regularly arranged in parallel series on either side of the 

 vertebrals; tubercles in parallel diagonal series; average size greater than 45 

 mm. from snout to vent 18 



