t the two kinds are neither subspecies of a single species, nor
individual variants of a widespread, monotypic species, but probably are
two different species. We agree that one, most likely the smaller
_toltecus_, may eventually prove to be a northern subspecies of
_cinereus_.

_=Myotis occultus=_ Hollister.--A single specimen of this species
(67491) from 1 mi. N, 1/2 mi. E San Miguel provides the first certain
record from Sinaloa, and is indistinguishable from specimens from
Alamos, Sonora, that were referred to _occultus_ by Hall and Dalquest
(1950:587). Miller and Allen (1928:100) identified a skin alone from
Escuinapa as _occultus_, but Hall and Dalquest (_loc. cit._) later
assigned this specimen provisionally to _M. fortidens_ on geographic
grounds and because it agreed in color with undoubted specimens of the
latter from Guerrero. Specimens from south of San Miguel and north of
the undoubted range of _fortidens_ are needed in order to ascertain
whether the two kinds are distinct species or instead only subspecies of
a single species.

The Sinaloan bat was taken in a mist net stretched over a drainage ditch
adjacent to the R['i]o del Fuerte on the night of June 19-20, 1955, by R.
H. Baker. Several other kinds of bats were obtained (shot or netted) at
the same place, among which was one specimen of _Myotis velifer_. The
specimens studied of _occultus_ from Sinaloa and Sonora are clearly
separable from specimens of _velifer_ from the same region (Sonora and
northern Sinaloa) in having paler (more reddish) pelage, shorter
forearm, smaller skull, relatively broader rostrum, and four fewer
teeth.

_=Myotis velifer velifer=_ (J. A. Allen).--Three specimens from the
following localities in northern Sinaloa provide the first records of
the species from the state: El Fuerte (75234); R['i]o del Fuerte, 1 mi. N,
1/2 mi. E San Miguel (67490); R['i]o del Fuerte, 10 mi. NNW Los Mochis
(61149). The subspecies _M. v. velifer_ has been reported previously
from the adjacent states of Chihuahua, Durango, and Sonora.

A female (61149) obtained on June 8, 1954, carried a single embryo that
measured 3 mm. in crown-rump length.

_=Lasiurus borealis teliotis=_ (H. Allen).--A female from 10 mi. NNW Los
Mochis (61172), obtained on June 8, 1954, represents the first record of
the species from Sinaloa, and is tentatively referred to this
subspecies. It resembles cranially, but is paler than, Californian
specimens seen of _teliotis_.