MEXICAN TAILLESS AMPHIBIANS 33 



tially concealed by tubercles; first finger longer than second; 

 subarticular tubercles on distal phalanges of fourth toe gen- 

 erally single, occasionally double; a tarsal fold; head-and- 

 body length, 60 to 87 mm compactilis (p. 44) 



7. Head broad, flat or shallowly concave, and thin through, with- 



out raised cranial crests, or with only vestiges of such; snout 

 short, blunt; parotoid glands elevated, rounded or broader 

 than long, and studded with minute tubercles; skin of 

 upperparts with closely set small tubercles; coloration 

 ranging from light reddish brown to gray or even malachite 

 green; warts on upperparts tipped with red, orange, or yel- 

 low and encircled or partially encircled at base by narrow 

 black border; obscure black markings occasionally present on 

 limbs; underparts uniform white or spotted with darker color; 

 diameter of oval tympanum more than half that of orbit; 

 first finger longer than second; subarticular tubercles on dis- 

 tal phalanges of fourth toe single; a tarsal fold bearing row 

 of small tubercles; head-and-body length, 55 to 80 mm. punctatus (p. 60) 

 Head narrow or broad, but with distinctly raised cranial crests 8 



8. Parietal crests unusually swollen, merging with thickened post- 



orbital crests; supraciliary crests high, converging anteriorly; 

 supratympanic crest short and connecting with large swollen 

 subtriangular or ovoidal parotoid gland; interorbital region 

 concave; snout pointed, prominent; tympanum small, less 

 than one-half diameter of orbit and often rather indistinct; 

 skin of upperparts and upper surfaces of fore and hind 

 limbs with scattered small conical warts; underparts strongly 

 granular; upperparts (in alcohol) sooty brown with a few 

 indistinct markings of some lighter color; throat and chest 

 dusky or blackish; belly with irregular blotches of yellow; 

 under surfaces of fore and hind limbs irregularly marked 

 with yellow and some dusky color; first and second fingers 

 subequal; toes about two-thirds webbed, the penultimate and 

 last phalanx of fourth toe free; metatarsal tubercles of mod- 

 erate size; subarticular tubercles on distal phalanges of fourth 

 toe single or double; bicolored parotoid glands, black later- 

 ally and grayish superiorly; head-and-body length, 48 to 



75 mm cristatus (p. 48) 



Parietal crests when present not unusually swollen or expanded 

 laterally [parietal crests of Bufo valliceps considerably swol- 

 len in rare instances] 9 



9. Parotoid glands elongate, in contact anteriorly either with 



postorbital crest or with upper eyelid; no supratympanic 



crest 10 



Parotoid glands not in contact either with upper eyelid or with 

 postorbital crest, but separated by an interval of varying 

 width; parietal crests generally present, occasionally ves- 

 tigial; supratympanic crests present 11 



10. Parietal crests slender, short, and converging posteriorly; 

 supraciliary crests convergent anteriorly; interorbital space 

 wider than upper eyelid; postorbital crests very short, if 

 present, and not extending more than halfway across to- 

 ward tympanum; parotoid glands elongated, as large as or 

 larger than upper eyelid; tympanum cither distinctly out- 

 lined or largely concealed by tubercular skin and closely set 



