_Description._--The following description is based on KU 58069 from 6.2 kilometers south of Rayon Mescalapa, Chiapas, Mexico (Pl. 17). Adult male having a snout-vent length of 27.6 mm.; tibia length, 13.0 mm.; tibia length/snout-vent length, 47.1 per cent; foot length, 10.8 mm.; head length, 9.6 mm.; head length/snout-vent length, 34.7 per cent; head width, 9.2 mm.; head width/snout-vent length, 33.1 per cent; diameter of eye, 3.0 mm.; diameter of tympanum, 1.6 mm.; tympanum/eye, 53.3 per cent. Snout in lateral profile nearly square, slightly rounded above and below, and in dorsal profile blunt, almost square; canthus pronounced; loreal region concave; lips thick, rounded and flaring; nostrils protuberant; internarial distance, 2.5 mm.; internarial region slightly depressed; top of head flat; interorbital distance, 3.3 mm., much greater than width of eyelid, 2.5 mm. Thin dermal fold, from posterior corner of eye above tympanum to insertion of fore limb, covering upper edge of tympanum; tympanum nearly round, its diameter equal to its distance from eye. Forearm slender, lacking distinct fold on wrist; row of low, rounded tubercles on ventrolateral surface of forearm; pollex slightly enlarged, without nuptial spines; second and fourth fingers equal in length; subarticular tubercles round, that under fourth finger bifid; discs small, that of third finger noticeably smaller than tympanum; no web between first and second fingers; vestige of web between other fingers. Heels overlapping when hind limbs adpressed; tibiotarsal articulation reaches to middle of eye; no tarsal fold; inner metatarsal tubercle large, flat, and elliptical; outer metatarsal tubercle small, elliptical, slightly more distal than inner; subarticular tubercles round; length of digits from shortest to longest 1-2-5-3-4; third and fifth toes webbed to base of disc; fourth toe webbed to base of penultimate phalanx; discs smaller on toes than on fingers. Anal opening directed posteriorly at upper edge of thighs; no anal flap; pair of large tubercles below anal opening. Skin of dorsum and of ventral surfaces of forelimbs and shanks smooth; that of throat, belly, and ventral surfaces of thighs granular. Ventrolateral glands well developed, not reaching axilla or groin and broadly separated midventrally. Tongue cordiform, shallowly notched behind and only slightly free posteriorly; vomerine teeth 2-3, situated on small triangular elevations between ovoid inner nares; openings to vocal sac large, one situated along inner posterior edge of each mandibular ramus.