WHAT ARE BATS? 
227 
The other pair of limbs (the arms and hands) are of exceed- 
ing length. Both the arm and forearm are long — especially 
the latter — but it is the fingers which are so wonderfully drawn 
out, and they are webbed, like the toes of a water-fowl. More- 
over, the web not only connects these long fingers together, but 
also connects them with the sides of the body and with the legs 
(as far as the ankle); and does not stop even here, but continues 
on to the tail, thus connecting it with the two legs. 
This large web or membranous expansion has two names. 
The part belonging to the hand and joining the sides of the 
body (which is supported by the fingers as an umbrella by its 
rods) is termed the alar membrane. The part connecting the 
legs with the tail is called the interfemoral membrane. 
Looking more closely, however, we find that though the four 
fingers of each hand are thus bound together, the thumb is free, 
standing out at a wide angle, and furnished with a very long 
and strong, hooked claw. Of the four fingers, it is only the first 
which is clawed. 
The uses made by the bat of its singularly-formed limbs are, 
of course, in exact correspondence with their structure. The 
fore-limbs are true organs of flight ; the hind-limbs and tail 
have a rudder-like action. Besides flight (their predominant 
mode of motion), bats can crawl upon the surface of the earth 
with an awkward, shuffling gait. When so crawling, the wings 
are closed (the long fingers then lying side by side) and the 
animal rests on its wrists and hind-feet, the body being dragged 
forward by the help of the strong, hooked thumb nails, which 
also help it to climb with ease up any rough surface, even though 
perpendicular. 
When at rest, bats usually hang suspended, head downwards, 
by the claws of their feet, though occasionally they turn round 
and hang from the claws of their thumbs. 
Most nocturnal beasts have large eyes, but most bats have 
very small ones. 
This is perhaps due to the fact that 
guided by an extraordinarily delicate 
sense of touch — so delicate as to seem 
almost like a sixth sense. 
The external ear of most bats 
appears at first to be double — a 
very small one seeming to stand up 
inside the larger one. This appear- 
ance, however, is due merely to the 
very large development of a little 
piece which in ourselves projects backwards as a small rounded 
process guarding externally the opening of our ear, and called 
the tragus. 
Q '1 
bats in their flight are 
Head of Large-eared Bat. 
t, Tragus. 
