124 NOCTULE, OR GREAT BAT. 
it will be noticed that, as soon as the swallows retire to rest at dusk, after clearing the air 
of the diurnal insects, the bats issue from their homes, and take wp the work, performing 
the same task with the insects of night, as the birds with those of day. Then, as the 
dawn breaks, out come the swallows again, and so they fulfil their alternate duties. 
NOCTULE, OR GREAT BAT.—Noctulinia altivolans. 
The NocTuLs is not so pleasant a companion as the Long-eared Bat, for it gives forth 
a most unpleasant odour. Its cry is sharp and piercing, thereby producing another 
analogy with the swifts, which are popularly known by the name of “ Jacky-screamers.” 
The voice of all British bats is singularly acute, and can be tolerably imitated by the 
squeaking sound which is produced by scraping two keys against each other. There are 
many people whose ears are not sensible to the shrill ery of these animals—which, in 
some cases, 18 Té ather fortunate for them. I well remember being on Hampstead-heath, 
one summer's evening, when the air was crowded with bats hawking after flies, and their 
myriad screams were so oppressive, that I longed for temporary deafness. Yet my 
compan an accomplished musician—was perfectly insensible to the shrill cries, which 
seemed to pierce into the brain like so many needles. It is also known that many ears are 
deaf to the stridulous call of the grasshoppers. 
In order to show the sharply-pointed teeth of the insect-feeding bats, the skull of the 
common bat is here given. 
One use of the tail is, evidently, that it should act as a rudder, in order to guide the 
flight while the creature is on the wing. There is, however, another purpose which it 
serves, and which would never have been discovered, had not the bat 
a~ been watched. It seems that the female bat uses its tail, and the 
An membrane which stretches on either side from the tail to the hind legs, 
ESD); as a cradle, in which to deposit its young when newly born and com- 
paratively helpless. 
SUSU Bats are generally found to assemble in great numbers wherever 
they find a convenient resting-place, and in such localities as church 
towers, rocky caverns, hollow trees, and the like, they may be found by the hundred 
together. These numerous assemblies are the cause of a large deposition of guano, which 
consists almost wholly of the refuse of insects, such as wings, legs, and the harder coverings. 
In this guano are found, by the aid of the microscope, very many curious infusorial 
objects, which may be separated from the guano by the usual modes of preparation. 
The odour which arises from this substance is peculiarly sharp and pungent, and 
cannot easily be mistaken. The animals themselves are readily alarmed when disturbed 
in their home, they disengage themselves from their perches, and flap about in great 
dismay, knocking themselves against the intruder’s face, much as the great nocturnal 
