t be correlated either with sexual or ontogenetic
development. Since the glands are found in individuals from all parts of
the range, it is unlikely that there is a correlation between the
development of the glands and the environment.

[Illustration: FIG. 7. Diagrammatic view of ventral surfaces of
_Leptodactylus melanonotus_ (A) and _Leptodactylus occidentalis_ (B),
showing usual position and size of glandular areas. Approx. natural
size.]

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 Mexico show certain characters that
distinguish them from _Leptodactylus melanonotus_, as it is known
throughout the rest of Mexico. 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
Concepcion (UMMZ 113081), La Resolana (UMMZ 102104), and Tenachitlan
(UMMZ 113045-6). Records for _Leptodactylus occidentalis_ are: Alamos,
Sonora (AMNH 51356-65); Culiacan (AMNH 49511-9), Chele (UMMZ 110914),
and Rosario (UMMZ 113062) in Sinaloa; Ixtlan del Rio (UMMZ 102108), San
Blas (UMMZ 112814, 112994, 110892, 115543), and Tepic (UMMZ 115544) in
Nayarit; Ameca (UMMZ 102106-7) and La Cofradia on the south shore of
Lago de Chapala (UMMZ 102105) in Jalisco; and Tangamandapio, Michoacan
(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, Michoacan, Mexico.

_Microbatrachylus hobartsmithi_ Taylor, Univ. K