Adult males are noticeably smaller than females; measurements for 20 males and ten females from Apatzingán are, respectively: snout-vent length, 29.6-34.6 (32.3), 36.3-44.1 (40.8); tibia length, 12.6-15.1 (14.0), 16.5-19.0 (17.8); head width, 10.8-11.9 (11.3), 12.6-14.8 (13.7); head length, 11.2-13.2 (11.9), 13.1-14.8 (14.0). Brownish yellow ventral glands are present in some juveniles and in some adults collected in the dry season as well as in the rainy season. ~Leptodactylus occidentalis~ Taylor _Leptodactylus occidentalis_ Taylor, Trans. Kansas Acad. Sci., 39:349, 1937.--Tepic, Nayarit, México. Five km. W of Tangamandapio. On the night of June 11, 1958, this species was calling from a hyacinth-choked ditch. Although numerous individuals were heard, only one specimen was obtained. The frogs were calling from the tangled mat of hyacinths along with _Hyla eximia_, _Hypopachus oxyrrhinus ovis_, and _Rana pipiens_. Taylor (1936a:352) characterized this species as follows: "The narrow head, small maximum size (38 mm. for females, 33 mm. for males), the character of the postaxillary and postfemoral glands, the narrower groups of vomerine teeth, clearly distinguish this western Mexican form from the more robust, larger _melanonotus_ to the south. The call is likewise fainter and different in quality." Concerning the glands, Taylor (_loc. cit._) remarked: "There is a possibility that the horny excrescence covering the glands may appear only during the breeding season. This character is quite as strongly marked in females as in males." Bogert and Oliver (1945:324) concluded that the population of _Leptodactylus_ in northwestern México could not be distinguished from _melanonotus_ in other parts of the country and thus synonymized _Leptodactylus occidentalis_ with _melanonotus_. Bogert and Oliver (op. cit.: 324) stated that the extent as well as the presence or absence of ventral glands was highly variable in all samples examined by them.