other bats; and the presence of tufts of long differently-coloured
hairs over glands in the sides of the neck is another character in
common with that group. _Centurio senex_ (fig. 13) is the type of a
small genus distinguished from _Stenoderma_ and other genera of this
group by the absence of a distinct nose-leaf. Some naturalists make
this genus the type of a distinct subgroup, _Centurioneae_. Up to 1904
the genera, exclusive of _Centurio_, included in the _Stenodermateae_
were _Artibeus_ (with several sub-genera), _Vampyrops_ (also with
subgenera), _Mesophylla_, _Chiroderma_, _Stenoderma_ (with 3
subgenera), _Ectophylla_, _Ametrida_ (with 2 sub-genera), _Pygoderma_,
_Sturnira_ and _Brachyphylla_.

[Illustration: FIG. 13.--Head of Masked Vampire (_Centurio senex_).
From Dobson.]

The third subfamily, _Desmodontieae_, is represented only by the
blood-sucking bats, and distinguished by having _i._ 1/2, of which the
upper pair are cutting, the rudimentary molars, the very short
interfemoral membrane, and the blood-sucking habit. They are further
characterized as follows: Muzzle short and conical; nose-leaf
distinct; _p._ 2/3, _m._ 1/1 or 0/0; upper incisors occupying the
whole space between the canines; premolars narrow, with sharp-edged
longitudinal crowns; molars rudimentary or absent; stomach elongated,
and intestiniform. There are two genera, _Desmodus_, without calcar or
molars, and _Diphylla_, with a short calcar and a single rudimentary
molar on each side--restricted to Central and South America. _Desmodus
rufus_, the commoner species, is a little larger than the noctule bat,
and abundant in certain parts of South America, where it is
troublesome owing to its attacks upon domestic animals, sucking their
blood and leaving them weakened from repeated bleedings. (See
VAMPIRE.)

Free-tailed bats.

The fourth family of bats, unlike any of the three previous ones, has
a cosmopolitan distribution. These free-tailed bats, as they are
conveniently called, constituting the family _Emballonuridae_, present
the following distinctive features. The nostrils are of normal form
and without a nose-leaf. The premaxillae have their palatal portion
imperfectly developed, and united by a slender process with the
maxillae. The ears are large, with a small tragus. The middle finger
has two phalanges, and the index generally a single one. The fibula is