Dr. J. E. Gray on the Genera of Vespertilionide. 89 
IX.—Synopsis of the Genera of Vespertilionide and Noctilionide. 
By Dr. J. H. Gray, F.R.S., V.P.Z.8. &c. 
THE Insectivorous Bats without any nose-leaf may be divided 
into two families by the shape of the intermaxillary bones and 
the position of the upper cutting-teeth. 
The skulls of these Bats have generally a well-developed inter- 
maxillary separating the upper canines by a well-marked space. 
In Noctilionide the intermaxillary bones are united to the 
front, and the upper cutting-teeth are on the sides of the cen- 
tral suture, in the middle of the space between the canines. In 
Vespertilionide the intermaxillaries are separated by a notch in 
front, and the cutting-teeth are separated into two groups by 
this notch, and placed more or less near to the canines. 
These Bats have three grinders in each jaw on each side, and 
from one to three false grinders; the fore ones are often very 
small and rudimentary, and the front one is often placed behind 
the canines, within the tooth-line, so that it cannot be seen from 
the outside. The genus Vespertilio has been divided, accord- 
ing to the number of these false grinders, into sections, and 
M. Gervais and Dr. Peters have formed several genera on the 
number of these false grinders. Thus, for example, three spe- 
cies of Plecotus have been formed into three genera, and placed 
in different sections of the family, on these characters; and the 
two species of North American Lasiuri differ in the number of 
these teeth, and ought, according to this system, to be similarly 
separated. 
I can only regard such characters as of secondary importance ; 
and I believe that the form of the tragus and antitragus would 
even form better characters for the separation of the species of 
the genus into sections. 
Dr. Peters, in the ‘ Proceedings of the Berlin Academy’ for 
1865, has published a list of the genera of Bats ; but he does not 
give any characters either for the tribes or the genera. 
Family Vespertilionide. 
Face simple. Nostrils on the front of the nose, simple. The 
cutting-teeth separated in the middle by a space, and placed 
near the canines. Grinders acutely tubercular, three on each 
side in each jaw, the hinder one short and broad; with one, 
two, or three false grinders in front of them. Intermaxillaries 
separate from one another in the front of the palate, leaving a 
notch between the cutting-teeth. 
I. Tail elongate, enclosed, and extended to the end of the elongated 
and produced inter femoral membrane. 
1. Ears separate, lateral ; the face short, broad, nearly bald ; fore- 
