CHECKLIST OF THE AMPHIBIA OF MEXICO 59 



12. Outer metatarsal tubercle one-thrrd or more of inner; a few tubercles on 



outer edge of tarsus; inner metatarsal tubercle smaller and more elon- 

 gate-oval than that of preceding species; large, outer palmar tubercle 

 partly fused to median; digits very slightly dilated at tips, without 

 transverse grooves; vomerine teeth reduced or absent; some variable 

 dorsal ridges, the skin usually granular; vomerine teeth reduced (or 

 occasionally absent); testicular membranes white; 40 mm. 



mexicanus (p. 62) 

 No tubercles on tarsus; tips of digits widened into small disks with trans- 

 verse grooves; heel much beyond tip of snout; heels overlapping much 

 when legs are folded; vomerine teeth small, weak; inner metatarsal 

 tubercle oval, rather small, less than three-fifths length of inner toe; 

 outer palmar tubercle fused to median; ventral disk distinct; gonadal 

 membranes black, inguinal gland yellowish (perhaps referable to Micro- 

 batrachylus) ; 44 mm saltator (p. 63) 



13. Heavy toadlike forms with or without a tarsal fold; a strongly defined 



ventral disk 14 



Smaller, slender froglike forms, lacking a tarsal fold; the head as wide as 

 body; ventral disk present but not strongly defined; more or less areo- 

 late, rough or striated ; heel to between eye and nostril 17 



14. A sharp-edged tarsal fold; a small web between the toes; head very wide; 



a small outer metatarsal tubercle; a large protuberant inner; 74 mm. 



laticeps (p. 63) 

 No trace of a tarsal fold; no trace of webbing between toes 15 



15. Limbs short; heel to tympanum; heels widely separated when legs are 



folded (7 mm.); skin above minutely corrugated, without tubercles; 

 outer metatarsal tubercle three-quarters of inner; tympanum about 

 three-fifths of eye diameter; eyelid greater than interorbital distance; 



78 mm cactorum (p. 63) 



Limbs longer; heel to eye; heels touch or overlap a little when Umbs are 

 folded; eyelid less than interorbital space 16 



16. Tympanum two-thirds to four-fifths diameter of eye; dorsal surface 



smooth; 90 mm latrans (p. 63) 



Tympanum scarcely one-half diameter of eye; dorsal surface rough, 

 granulate; 80 mm augusti (p. 63) 



17. An intratympanic fold; skin smoother, median palmar tubercle narrowed, 



elongate; limbs strongly barred with double white lines; 44 mm. 



bolivari (p. 64) 

 No intratympanic fold; supernumerary tubercles on hand very large; 

 skin rougher, tubercular; median palmar tubercle not strongly nar- 

 rowed; hind limbs not barred with double white lines; 43 mm. 



tarahumaraensis (p. 64) 



18. A distinct tarsal fold ^^ 



A tubercle present on tarsus instead of a fold 23 



19. A mere vestige of a web between toes; edges of canthus rostralis sharp; 



a pair of sinuous dorsal ridges from eye to rump, nearest together at 

 middle of body; tips of toes scarcely dilated; no distinct tarsal fold; 



40 mm matudai (p. 64) 



A small distinct web present between toes; edges of canthus not elevated. 20 



20. A vocal sac present in males; tubercles in occipital region tending to form 



a W-shaped pattern; toe disks rounder, wider than fingers; first and sec- 

 ond fingers subequal; toes one-third webbed; a slight, narrow, elongate 



tarsal fold extends half length of tarsus; 57.5 mm vocalis (p. 64) 



Vocal sac wanting in males 



