r forming a broad arch and finely denticulate; tooth
rows 2/3, the upper rows extending to the edge of the lips, subequal in
length, and slightly longer than lower rows, which also are subequal in
length; inner upper tooth row broken medially; inner lower tooth row
sometimes broken (Fig. 6).

The body is black dorsally and laterally, and bluish gray ventrally; the
tail musculature is brown and stippled with darker brown. The fins are
transparent and stippled with brown, the stippling being most pronounced
on the posterior two-thirds of the upper tail-fin.

[Illustration: FIG. 5. Tadpole of _Bufo occidentalis_ (UMMZ 94269) from
Barranca Seca, Michoacan. x 3.]

[Illustration: FIG. 6. Mouthparts of larval _Bufo occidentalis_ (UMMZ
94269) from Barranca Seca, Michoacan. x 20.]

Forty recently metamorphosed individuals average 18.9 mm. in snout-vent
length.

The relationships of this toad seem to be with _Bufo bocourti_ Brocchi,
an inhabitant of pine and oak forests in the uplands of Chiapas and
Guatemala. In _Bufo occidentalis_ the tympanum usually is indistinct and
sometimes completely covered, and it is absent in _bocourti_. _Bufo
occidentalis_ has a broader interorbital area and relatively shorter and
more rounded parotid glands than _bocourti_. The tadpoles of the two
species are nearly identical (see Stuart, 1943:12).

~Leptodactylus labialis~ (Cope)

_Cystignathus labialis_ Cope, Proc. Amer. Philos. Soc.,
17:90, 1877.--No type locality designated; type locality
restricted to Potrero Viejo, Veracruz, Mexico, by Smith and
Taylor (1950a:350).

_Leptodactylus labialis_, Brocchi, Mission Scientifique au
Mexique et dans l'Amerique Centrale, pt. 3, sec. 2, livr.
1:20, 1881.

Apatzingan (26); Capirio (5); Cofradia (9); El Sabino (4);
Lombardia; Rio Tepalcatepec, 27 km. S of Apatzingan (2).

In the Tepalcatepec Valley this frog reaches the northernmost known
limit of its range in western Mexico. Although the species is abundant
in the valley, it apparently is absent from the coastal lowlands. In the
Tepalcatepec Valley _Leptodactylus melanonotus_ seems to be more
abundant than _labialis_. In the rainy season both species have been
heard calling from the same ponds and flooded fields.

There are only slight differences in size between the sexes;
measurements of 20 males and eight females are, respectively: snout-vent
length, 32.3-39.5 (35.1), 34.1-39.2 (37.2); tibia le