y absent, if present not
extending between metatarsal tubercles; tarsus bearing
tarsal folds or not; toes free of webbing, extensive lateral
fringes present in some species; terminal phalanges pointed,
not T-shaped; sternum bearing bony style; sphenethmoid not
truncate anteriorly; nasals in contact medially; maxillary
and quadratojugal in articular contact; anterior arm of
squamosal not in contact with maxillary; dermal cranial
elements not involved in integumentary-cranial
co-ossification; prevomers large, bearing dentigerous
processes; maxillary and premaxillary bones dentate;
occipital condyles separated; tadpole free living.

_Composition._--Sixty species according to Smith and Taylor
(1948); 54 according to Gorham (1963); Argentinian authors
have described several more in recent years.

_Distribution._--Southern Sonora, Mexico, and southern Texas
throughout the Central and South American lowlands to
Argentina. Also known from Hispaniola and Puerto Rico in the
Greater Antilles and a few islands in the Lesser Antilles.

_Entymology._--Greek (_leptos_ + _dactylus_) meaning slender
toes.

Genus ~Syrrhophus~ Cope, 1878

_Type-species._--_Syrrhophus marnockii_ Cope, 1878

_Diagnosis and definition._--Small to medium sized frogs (18
to 40 mm. snout-vent) having slight to prominent digital
expansions with transverse groove at tip of each digit;
lumbo-inguinal and inguinal gland flattened, irregular in
outline, not compact and oval; axillary glands present or
not; plantar supernumerary tubercles numerous, more than
eight, usually extending between metatarsal tubercles;
tarsus lacking tubercles or folds; toes free or basally
webbed; terminal phalanges T-shaped; sternum cartilaginous,
lacking bony style; sphenethmoid not truncate anteriorly;
nasals in contact medially; maxillary and quadratojugal in
articular contact; anterior arm of squamosal not in contact
with maxillary; dermal cranial elements not involved in
integumentary-cranial co-ossification; prevomers large,
usually lacking dentigerous processes and teeth; maxillary
and premaxillary bones dentate; occipital condyles
separated; development direct.

_Composition._--Thirteen species; the species described as,
or later referred to, _Syrrhophus_ from Lower Centr