THE LONG-EARED BAT. 
293 ' 
length, and strength. The pre-molars again are exceedingly variable ; there may be three or two on 
each side in both jaws, or one on each side in the upper and two in the lower jaw, but the occurrence 
of two above and three below is very rare. As a rule, when there are more than one pre-molar on 
each side in the upper jaw, the hindmost of them which is close to the true molars is larger than 
the one or two nearer the canine (see figure, p. 29'2), and the latter are often inserted within the line 
of the row of teeth. The true molars are three on each side in both jaws ; they are well -developed, 
and show the characteristic sharp W-shaped cusps very distinctly. 
The V espertilionkhe are all, so far as is known, strictly insectivorous in their habits. They are 
found generally distributed throughout the temperate and warm regions of both hemispheres. It is to 
LONG-EARED RATS IN FLIGHT. 
this family that nearly all the European Bats belong, and it includes all the British species, except the 
two Horseshoe Bats which have been already described. 
THE LONG-EARED BAT * 
This common British species is known by the large size of the ears, which are united by 
their inner margins over the middle of the crown of the head. Hence this group, the IHecot/L of 
authors, may be regarded as naturally forming a sort of stepping-stone from the Megaderms, with their 
extravagant dermal developments, to the more commonplace “ Vespertiliones. ,> In the Long-eared 
Bat this character is very striking, the ears being nearly seven-eighths as long as the head and 
body. The organs are quite thin and membranous, resembling those of the Megaderms already 
described, and they are traversed longitudinally by three thin threads of cartilage, which apparently 
serve by their elasticity to support the ears in an ei;ect posture. From the middle thread of cartilage 
38 
* Plecot us auritus. 
