CHECKLIST OF THE AMPHIBIA OF MEXICO 79 



9. Femur (thigh) immaculate 10 



Femur with at least some pigment 11 



10. Dorsum whitish with a triangular brown spot on occiput, connected 



or not with another blotch or blotches on back; stripe on side of 

 head and from eye more or less continued to groin; distal subarticular 

 tubercle of fourth finger double; fingers one-half or more webbed ; vo- 

 merine teeth present; 27 mm ebraccata (p. 84) 



No triangular dark spot on head or back; a pair of brown lines often 

 visible on anterior one-half or two-thirds of back; limbs frequently- 

 barred with darker; toes one-third (or slightly less) webbed; the 

 dark stripe from tip of snout to groin, bordered above with a lighter 

 stripe or not; 23 mm robertraertensi (p. 84) 



11. Dark pigment confined to dorsal side of femur; vomerine teeth present. 12 

 Pigment on dorsal and posterior parts of femur appearing as a sparse 



peppering 13 



12. A larger species, with a conspicuous axillary web; posterior surface 



of thigh red or orange (which fades, leaving no trace) ; fingers much 

 more than one-half webbed; distal tubercle of fourth finger single; 

 an indistinct tarsal fold; a vocal sac in males; no canthus rostralis; 



42 mm loquax (p. 84) 



Smaller species with an irregular dark brown or vinaceous pattern 

 on back; sometimes the shoulder spot has an X-shape; fingers one- 

 fourth or less webbed; pigment on femur may extend length of dorsal 

 surface of femur or only part way across underwocdi (p. 85) 



13. A conspicuous axillary web; hand half or more webbed; outer tubercle 



of fourth finger single; uniform or indefinitely spotted above; no 

 distinct tarsal fold; canthus distinct; vomerine teeth invariably 

 present; tympanum wider than its distance from eye; vocal sac 



in male; 38 mm rickardsi (p. 85) 



Axillary web slight or absent 14 



14. Hand with only slight vestige of web; vomerine teeth variable or 



absent 15 



Hand half or more webbed; no vocal sac in male; tympanum nar- 

 rower than its distance from eye, less than half diameter of eye; heel 

 to between eye and nostril; ventral surface of tarsus and posterior 

 surface of femur pigmented; 43.5 mm rozellae (p. 86) 



15. A broad dorsolateral pinkish-white stripe from eye to near groin; 



vomerine teeth absent (rarely present but if so, small, inconspicuous) ; 

 tympanum a Uttle more than one-third eye; canthus angular; heel 



to between eye and tip of snout; 25 mm picta (p. 85) 



No broad dorsolateral stripe; sometimes a very narrow line without 

 pigment between dorsal and lateral coloration; vomerine teeth 

 usually present in adults, often absent in young; tympanum about 

 one-half of eye; canthus absent; heel to anterior part of eye; 30 

 mm smithi (d. 85) 



16. Skin leathery, thickly covered with a glandular layer (parotoid?), not 



confined on back; under lens very numerous, minute, oily-yellow 

 (somewhat whitish) points visible in skin; no web or only a vestige 

 between fingers; a heavy supratympanic fold; nuptial callosities of 

 first finger of males covered with black, horny spines (also present on 

 second and third fingers) ; anal flap usually elongate, bringing anus to 

 near lower level of femora; medium large to large {crassa has not been 

 examined, but very probably all these characters obtain in that 

 form) bistincta group 17 



