Aside from the differences in the ventral glands, the call is different in the two populations. The call of _Leptodactylus occidentalis_ is a rather harsh "wack, wack, wack" as contrasted with the more nasal "woink, woink, woink" of _melanonotus_. Sound spectrographs are needed to analyze the differences in calls. None of the specimens of _occidentalis_ examined approaches in size the largest individuals of _melanonotus_; possibly the size of the frogs is another valid character for separating the species. On the basis of the above data it is evident that the frogs in northwestern México show certain characters that distinguish them from _Leptodactylus melanonotus_, as it is known throughout the rest of México. It is not known for certain that _melanonotus_ and _occidentalis_ are sympatric. Several series of old, poorly preserved specimens from Nayarit and Sinaloa cannot be placed in either species, for none has visible ventral glands. _Leptodactylus melanonotus_ is known from Acaponeta, Nayarit (AMNH 43913-25), and the following localities in Jalisco: Barro de Navidad (UMMZ 118098), La Concepción (UMMZ 113081), La Resolana (UMMZ 102104), and Tenachitlán (UMMZ 113045-6). Records for _Leptodactylus occidentalis_ are: Álamos, Sonora (AMNH 51356-65); Culiacán (AMNH 49511-9), Chele (UMMZ 110914), and Rosario (UMMZ 113062) in Sinaloa; Ixtlán del Río (UMMZ 102108), San Blas (UMMZ 112814, 112994, 110892, 115543), and Tepic (UMMZ 115544) in Nayarit; Ameca (UMMZ 102106-7) and La Cofradía on the south shore of Lago de Chapala (UMMZ 102105) in Jalisco; and Tangamandapio, Michoacán (UMMZ 119145). From these scattered records it appears that _Leptodactylus occidentalis_ in the southern part of its range stays in the uplands, whereas _melanonotus_ is confined to the lowlands. ~Microbatrachylus hobartsmithi~ (Taylor) _Eleutherodactylus hobartsmithi_ Taylor, Trans. Kansas Acad. Sci., 39:355, 1937.--Uruapan, Michoacán, México. _Microbatrachylus hobartsmithi_ Taylor, Univ. Kansas Sci. Bull., 26:501, November 27, 1940. Cascada Tzararacua (6); 21 km. W of Ciudad Hidalgo; 29 km. E of Morelia; Puerto Hondo; San José de la Cumbre (13); Uruapan (2); Zitácuaro.