_Distribution._--Low to moderate elevations from Sinaloa, Mexico, to Guatemala on the Pacific versant; from the Edwards and Stockton plateaus of Texas to British Honduras on the Caribbean versant. _Etymology._--Greek, emendation of _syrrhaptos_, meaning sewn together in reference to the united outer metatarsals. Genus ~Tomodactylus~ Guenther, 1900 _Type-species._--_Tomodactylus amulae_ Guenther, 1900. _Diagnosis and definition._--Small frogs (20 to 35 mm. snout-vent length) having digital expansions or not, with transverse groove across tip of each digit; lumbo-inguinal gland prominently elevated, compact, oval, often patterned; axillary glands absent; plantar supernumerary tubercles numerous, more than eight, usually extending between metatarsal tubercles; tarsus lacking tubercles or folds; toes free; 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 bearing dentigerous processes; maxillary and premaxillary bones dentate; occipital condyles separated; development direct. _Composition._--Ten species. _Distribution._--The southern edge of the Mexican Plateau from Sinaloa to Veracruuz and onto the Oaxaca highlands and Sierra Madre del Sur. _Etymology._--Greek (_tomis_ + _dactylus_) meaning knife toe; in reference to either the sharp subarticular tubercles or the unwebbed toes. DISCUSSION The preceding definitions only slightly alter the present generic limits of Mexican leptodactylids. Two species, previously regarded as _Eleutherodactylus_, are transferred to the new genus _Hylactophryne_. The arrangement of the species of _Syrrhophus_ and _Tomodactylus_ remains the same as concluded by Dixon (1957), Duellman (1958), and Firschein (1954) in their reviews of the genera. Lumbo-inguinal glands are most prominent in the genera _Pleurodema_ and _Tomodactylus_. Various nondescript glands are present in many genera, but none is so well developed as those of _Pleurodema_ and _Tomodactylus_.