PTEROPID A, 99 
Pacific Oceans, There is a general similarity in the colouring; and 
. Specimens found in the same locality or island often vary consider- 
ably from one another, even when examination of the skull and teeth 
shows that they are one species. On the other hand, specimens from 
very different localities often resemble one another so much in their 
external colouring that it is difficult to distinguish them in any descrip- 
tion that can be given; but when the skull and teeth are examined, 
they prove to be very distinct species. Under these circumstances 
the locality is an important character in determining the species. 
This observation is applicable to other families of Bats; indeed the 
species of these animals are so imperfectly known, and the material 
in the Museums is so imperfect, that the best one can attempt to do 
is to get what is contained in the Museum into groups, leaving suc- 
ceeding naturalists to determine if they are species or varieties. 
Many of the characters given by Temminck and others as cha- 
racteristic of the species depend on the art or want of talent of the 
preserver. 
Synopsis OF Trizrs anD GENERA. 
Section A. Teeth 34. True grinders 3, hinder small. False grinders 3 ; 
Sront minute, often deciduous 
Tribe I. Przropina.  Cutting-teeth 4; lower ina regular series, Task 
none. Giand of penis bony. 
1, SpectRum. Head round; face narrow. Ears small, hidden. Wings 
from the sides of the hairy back.. 
2. Prerorpus. Head elongate; facebroad. Earsexposed. Wings from 
the sides of the back. Back hairy. 
3. EunycseRis. Head elongate; face broad. Ears exposed. Wings 
only attached to the vertebral line; the part over the back bald, or 
nearly so. 
Tribe II. Macroauossina. Cutting-teeth 4; lower in a regular series. 
Tail-end free. Gand of penis fleshy. 
* Face very long, slender. Cutting-teeth isolated, in an arched series. 
Grinders compressed, smail. 
4, NoToprEris. Wings only attached to the vertebral line. Part over 
the back bald. Head very long; face slender. Tail very long. 
False grinders none. 
5. Macroatossus. Wings from the sides of the hairy back. Head very 
long ; face very slender. Tail short. False grinders 4, compressed. 
** Face broad. Cutting-teeth in a transverse series. Grinders thick. 
6. XanTHARPyI4. Wings from the sides of the hairy back. Head elon- 
gate; face tapering. Grinders far apart in front. Fur short, ad- 
pressed. : 
7, ELEUTHERURA. Wings from the sides of the hairy back. Head 
elongate ; face broad. Grinders close together. Fur soft, spreading. 
‘Tribe II. Cernarorina. Cutting-teeth 2; lower crowded before the 
base of the canines. Tatl-end free. Index finger not clawed. 
8. CepHaLores. Face short. Grinders close; upper’ false grinder 
wanting. Upper cutting-teeth broad. 
u 2 
