inguinal
gland as a generic character in Mexican eleutherodaycty-lines. Lynch
(1965) showed that _Eleutherodactylus_ and _Microbatrachylus_ cannot
be separated by the nature of the gland or the condition of the
prevomers (dentate or not). _Syrrhophus_ and _Tomodactylus_, as defined
by Smith and Taylor (1948), are not generically distinct because of
overlap in the condition of the prevomers and in the development of the
gland. Firschein (1954) stated that _Syrrhophus_ differed from
_Tomodactylus_ by having an axillary gland, but it is now known that
one species of _Syrrhophus_ lacks the gland.

The inguinal glands of _Eleutherodactylus_ and _Syrrhophus_, if
present, are diffuse, irregular in outline, and generally not
prominent; in _Tomodactylus_ the gland is higher on the body (a
lumbo-inguinal gland), compact, oval in outline, and prominent (Fig.
1). Axillary glands occur in most _Syrrhophus_ but are not known in
_Tomodactylus_ or _Eleutherodactylus_.

Hands and feet

The tips of the digits are laterally expanded in most
_Eleutherodactylus_, _Syrrhophus_, and _Tomodactylus_. Two species
of _Eleutherodactylus_ (_augusti_ and _tarahumarensis_) and two
_Tomodactylus_ (_angustidigitorum_ and _grandis_) lack any expansion
of the digital tips. All but two of the species of eleutherodactyline
frogs (_E. augusti_ and _E. tarahumarensis_) have a transverse groove
across the tips of the digits (Fig. 2).

[Illustration: FIG. 2. Palmar views of the hands and lateral views of
the tip of the third digits of _Eleutherodactylus alfredi_ (left, KU
93994, x 5) and _Hylactophryne augusti_ (right, KU 102594, x 3).]

Supernumerary tubercles rarely are present on the feet of
_Eleutherodactylus_, but are present and numerous in every species of
_Syrrhophus_, _Tomodactylus_, and in the members of the _augusti_ group
of _Eleutherodactylus_ (Fig. 3). The tubercles are small and numerous
in _Syrrhophus_ and larger in _Tomodactylus_ and the _Eleutherodactylus
augusti_ group. Most species of _Eleutherodactylus_ have no plantar
supernumerary tubercles; a few species have such tubercles, which never
extend between the metatarsal tubercles as in _Syrrhophus_ and
_Tomodactylus_.

[Illustration: FIG. 3. Plantar views of feet of _Eleutherodactylus
alfredi_ (left, KU 93994, x 4.5), _Syrrhophus pipilans nebulosus_
(middle, KU 58900, x 7.5), and _Hylactophryne augusti_ (right, KU
102594, x 3) showing differences in size and arrangement of
supern