All the. teeth of the lower jaw touch each other; in the upper
jaw the incisors are separated by a wide interspace from the canine.
The dentition of the Long-eared Bat (Plecotus auritus) differs
from the foregoing chiefly by the absence of one of the small pre-
molars on each side of the upper jaw. In the Horse-shoe Bats
(Rhinolophus, PI. 112, fig. 5)/ the Barbastelles (Barbastellus), the
Noctule (Vespertilio Noctula, PI. 112, fig, 2), and the Pipistrelle
(Vespertilio pipistrellus), the small premolars reduced to one on
each side of both jaws, are extremely minute, and seldom visible
from without. In the Serotine (Vespertilio serotinus, PI. 112, fig. 3)
the rudimental premolar is entirely wanting in the upper jaw, but
remains in the lower; and this condition of the molar series also
characterises the genera Rhinopoma, Noctilio, and many species
of Molossus and Nycticeus. In the genus Nycteris (PL 112, fig.
6 and 7) the small premolars are absent in both jaws ; and the molar
series is reduced to the large premolar and three true molars, which are
present on both sides of both jaws, in all the foregoing Bats.
The Bats with ciliated tongues, (Glossophaga, PI. 112, fig. 4, 41),
have three premolars and three true molars on each side of both
jaws, rather small and slender canines, and two minute incisors on
each side of both jaws.
The following are examples of the variation in the number of
incisive teeth: — in Taphozous perforatus, Geoff, and the species of
Megaderma : ~E{ in Molossus and Myoptera: in Nyctinoma, Rhinopoma,
Rhinolophus and Dysopus: g in Vespertilio lasiurus and V.
paradoxus: |±f in Noctilio : tf in Phyllostoma, Glossophaga and
Mormoops: g in Plecotus, Nycteris (PI. 112, fig. 6“ ), and in most
species of the genus Vespertilio, as restricted by modern Naturalists.
The molar teeth have a more trenchant character and
fewer points in the Leaf-nosed Bats (Phyllostoma) of South
America, which are commonly called Vampyres; their canines
also, which are remarkably long and strong, sharp-pointed and
vertical in position, indicate a higher kind of animal diet than
that of the ordinary insectivorous Bats. The premolar teeth
are better developed than usual; in the Phyllostoma hastatum
the first upper premolar has a strong, thick pointed crown,
with an internal and posterior talon; the second premolar is
larger than the first, with a triedral crown, and an anterior
and posterior talon at the base of the long, sharp middle cusp.
The first and second true molars have sub-compressed quin-
que-cuspid crowns ; the third molar is compressed from before
backwards, and has a tri-cuspid crown. The first and second
premolars below are simple and larger than those above, especially
the first; the first and second true molars have two large external
and three small internal cusps, and the last molar differs only by
a slight inferiority of size.
The dentition of the true hlood-sucking Vampire Bats, which
form the genus Desmodus (PI. 112, fig. 9) deviates, as might be
anticipated, in a remarkable degree from that of the Insectivorous
Bats : the crushing instruments required for the food of those species
are not needed ; and the true molars, with their bristled crowns, are
entirely absent in the Desmodus. The teeth at the fore-part of the
mouth are especially developed and fashioned for the infliction of
a deep and clean triangular puncture, like that made by a leech. The
incisors (i) are two in number above, closely approximated, one
in each intermaxillary bone, with a very large, compressed, curved,
and sharp-pointed crown, implanted by a strong fang which extends
into the maxillary bone. The upper canines have similar large,
lancet-shaped crowns, and their bases touch those of the incisors.
In the lower jaw the incisors are two in number on each side, much
smaller than the upper pair, and with bilobed crowns. The lower
canines. are nearly equal in size to those above. The molar series
is reduced above to two very small teeth, each with a simple compressed
conical crown, implanted by a single fang. The first two
molars below resemble those above ; but they are followed by a
third which has a larger compressed and bilobed crown, implanted
by two fangs ; this tooth corresponds with the last premolar in the
more normal genera of Insectivorous Bats. The dental formula
of the true Vampire-bat (Desmodus) is thus reduced to :—
m• . B : -. eMHfm pm. E—S I: = 2oUn .m(i) 2—2 1—1 ’ 1 3—3 , . The opposite extreme which the aberrant varieties of the
(1) The intestinal canal, like the dentition, is modified in conformity with the easily
assimilated food, viz, the blood of living animals, on which the true Vampires habitually