ad leading east from the village of Perote for about
2 kilometers to a small park. The frogs were found in the stream at
elevations of 50 to 100 meters higher than the park. The stream flows
through a ravine supporting open, dry pine forest. Although the stream
was searched thoroughly in February, 1966, no frogs were found. In July,
1966, adults and juveniles were found in crevices and under overhanging
rocks behind small cascades and waterfalls by day and sitting on rocks
and branches in the spray of cascades at night.

The specific name _siopela_ is derived from the Greek _siopelos_,
meaning silent, and alludes to the absence of a voice in this species.

Hyla altipotens new species

Plate 19

_Holotype._--Adult male, KU 101001, from 37 kilometers (by road) north
of San Gabriel Mixtepec (kilometer post 183 on road from Oaxaca to
Puerto Escondido), Oaxaca, Mexico, elevation 1860 meters; obtained on
February 19, 1966, by William E. Duellman.

_Paratypes._--KU 101002-6 collected at the same locality on February 19
and 20, 1966, by William E. Duellman, and KU 101008 from 33 kilometers
(by road) north of San Gabriel Mixtepec, Oaxaca, Mexico, elevation 1675
meters; obtained on February 20, 1966, by Linda Trueb.

_Diagnosis._--A member of the _Hyla taeniopus_ group characterized by a
yellow venter, yellow flecks on posterior surfaces of thighs,
bronze-colored stripe from snout, along canthus and edge of upper eyelid
to point above arm, pointed snout, smooth dorsum, and no sexual
dimorphism in shape of snout.

_Description of holotype._--Adult male having a snout-vent length of
68.8 mm.; tibia length 36.2 mm., 52.6 per cent of snout-vent length;
foot length (measured from proximal edge of inner metatarsal tubercle)
31.1 mm., 45.2 per cent of snout-vent length; head length 20.2 mm., 29.4
per cent of snout-vent length; head width 20.0 mm., 29.1 per cent of
snout-vent length. Snout in lateral profile acutely rounded, protruding
beyond tip of lower jaw, in dorsal profile pointed; canthus angular;
loreal region flat; lips thick, barely flared. Snout long; nostrils
slightly protuberant, directed dorsolaterally, situated about two-thirds
distance from anterior corner of eye to tip of snout; internarial
distance 5.6 mm.; internarial area slightly depressed; top of head flat;
interorbital distance 6.0 mm., 30.0 per cent of width of head; width of
eyelid 4.7 mm., 23.5 per cent of width of head. Diameter of eye 6.2 mm.;
heavy d