_) _leisleri_, represent another group; and the common
pipistrelle, _V._ (_Pipistrellus_) _pipistrellus_, yet another, with
_p._ 2/2. The only other group that need be mentioned is one
represented by the North American _V._ (_Lasionycteris_)
_noctivagans_, with _p._ 2/3. The African _Laeephotes_, the Chinese
_Ia_, and the Papuan _Philetor_ are allied genera, each with a single
species. _Chalinolobus_ and _Glauconycteris_ have the same general
dental character as _Vespertilio_, but are distinguished by the
presence of a lobe projecting from the lower lip near the gape; the
former, with _p._ 2/2, is represented by five Australasian species,
one of which extends into New Zealand; while the latter, with _p._
1/2, is African. The species of _Glauconycteris_ are noticeable for
their peculiarly thin membranes traversed by distinct reticulations
and parallel lines. _Scotophilus_, with _i._ 1/3, _p._ 1/2, includes
several species, restricted to the tropical and subtropical regions of
the eastern hemisphere, though widely distributed within these limits.
These bats, though approaching certain species of _Vespertilio_ in
many points, are distinguished by the single (in place of two) pair of
unicuspidate upper incisors separated by a wide space and placed close
to the canines, by the small transverse first lower premolar crushed
in between the canine and second premolar, and, generally, by their
conical, nearly naked, muzzles and thick leathery membranes. _S.
temmincki_ is the commonest bat in India, and appears often before the
sun has touched the horizon. _S. gigas_, from equatorial Africa, is
the largest species. _Nycticejus_, with the same dental formula as
_Scotophilus_, is distinguished, by the first lower premolar not being
crushed in between the adjoining teeth, and the comparatively greater
size of the last upper molar. It includes only the North American _N.
humeralis_ (_crepuscularis_), a bat scarcely larger than the
pipistrelle. The hairy-membraned bats of the genus _Lasiurus_
(_Atalapha_), with _i._ 1/3, _p._ 2/2 or 1/2, are also limited to the
New World, and generally characterized by the interfemoral membrane
being more or less covered with hair and by the peculiar form of the
tragus, which is expanded above and abruptly curved inwards. In those
species which have two upper premolars the first is extremely small
and internal to the tooth-row. The gen