umerary tubercles.]

Tarsal folds and tubercles are lacking in _Syrrhophus_, _Tomodactylus_,
and the _augusti_ group of _Eleutherodactylus_. Several species of
_Eleutherodactylus_ lack tarsal folds and tubercles, but in nearly
every species group, one or more species possess either an inner tarsal
fold, inner tarsal tubercle(s), or outer tarsal tubercles.

The terminal phalanges of _Syrrhophus_, _Tomodactylus_, and all
_Eleutherodactylus_ (except the frogs of the _augusti_ group) are
distinctly T-shaped. In the latter, the bones are knob-shaped distally
(Fig. 4). T-shaped terminal phalanges also are present in _Lithodytes_
and _Trachyphrynus_ but not in other leptodactylid genera. At least one
species of _Eupsophus_ (_E. quixensis_) has terminal phalanges that
resemble those of the _Eleutherodactylus augusti_ group. Several
species of _Eleutherodactylus_, _Syrrhophus_, and _Tomodactylus_ with
slender fingers have T-shaped terminal phalanges although the terminal
dilations proportionately are only scarcely wider than the finger tips
in the _Eleutherodactylus augusti_ group. The presence of a terminal
groove at the tip of the finger is an external indicator of the
T-shaped terminal phalanges.

[Illustration: FIG. 4. Terminal phalanges of four leptodactylid frogs
(all x 13.5). (a) _Eleutherodactylus mexicanus_, KU 55593; (b)
_Eupsophus roseus_, KU 84731; (c) _Eupsophus quixensis_, UIMNH 59643;
and (d) _Hylactophryne augusti_, KU 56192.]

Skull

All Mexican eleutherodactyline frogs have quadratojugal-maxillary
articulations, completely roofed skulls in adults, median contact of
the nasals, separated occipital condyles, and large prevomers. The
premaxillae of all species are visible when the skulls are viewed from
directly above. The pterygoid lacks a medioventral flange and does not
meet the palatine. In no species is the anterior arm of the squamosal
in contact with the maxillary. Of the numerous species examined (30
_Eleutherodactylus_, four _Syrrhophus_, and four _Tomodactylus_), the
species in the _Eleutherodactylus augusti_ group are unique in having a
sphenethmoid with a blunt anterior edge.

Pectoral Girdle

All species have large cartilaginous plates in the pectoral girdles;
none possesses a bony style. No divergent modifications of the clavicle
and coracoid bones are known in the family.

GENERIC ACCOUNTS

Genus ~Eleutherodactylus~ Dumeril and Bibron, 1841

_Type-species._--_Hylodes ma