incomplete. The tail is generally short, and always partly free from
the interfemoral membrane. There is generally only a single pair of
upper incisors, separated by gaps from the canines, and from one
another in the middle line.

The distinctive feature of these bats is the free tail-tip, which
pierces the interfemoral membrane to appear on its upper surface, and
may project beyond its margin. As a rule, these bats may also be
recognized by the peculiar form of the muzzle, which is obliquely
truncated, the nostrils projecting more or less in front beyond the
lower lip, by the first phalange of the middle finger being folded in
repose forwards on the upper surface of the metacarpal bone, and by
the upper incisors. Although cosmopolitan, these bats rarely extend
north or south of the thirtieth parallels of latitude.

[Illustration: FIG. 14.--Ear of _Emballonura raffrayana_. From
Dobson.]

The family may be divided into two subfamilies, of which the
_Emballonurinae_ is characterized by the incomplete premaxillae, the
presence of only one phalange in the index finger, and the short tail.
The dental formula is generally _i._ 1/3 (sometimes 2/3 or 1/2), _c._
1/1, _p._ 2/3, _m._ 3/3. This subfamily may be further subdivided into
subgroups or sections of which the first, _Embalionurae_, is
characterized by the slender tail perforating the interfemoral
membrane, so as to appear on its upper surface; the legs long, with a
slender fibula; the incisors weak; and the premolars 2/2. The typical
genus _Emballonura_ presents the following features: _i._ 2/3,
extremity of the muzzle more or less produced beyond the lower lip,
forehead flat. The genus contains several species, inhabiting islands
from Madagascar through the Malay Archipelago and Siam to the
Navigator Islands. _Coleura_, with _i._ 1/3, the extremity of the
muzzle broad, and the forehead concave, has two species from East
Africa and the Seychelles. _Rhynchonycteris_ is distinguished from
_Coleura_ by the produced extremity of the muzzle. The single species,
_R. naso_, from Central and South America, is common in the vicinity
of streams, where it is usually found during the day resting on the
vertical faces of rocks, or on trunks of trees growing over water; it
escapes notice owing to the greyish colour of the fur of the body and
of small tufts on the antebrachial membrane counterfeiting the
weath