THE BATS 



85 



of the glands between the eyes and the nostrils, making the face 

 even rounder and wider. There is a small additional expansion 

 of skin behind the bony spur. As regards the teeth, there are 

 two pairs of incisors above and three pairs below ; only one pair 

 of premolars in the upper jaw and two pairs in the lower jaw ; 

 and, of course, three pairs of molars above and below. 



Serotine Bat {Vespertilio serotinus) : to show (a) shape of ear; (h) naked three-cornered space 

 on under hp ; {c) remains of sucker disc on ball of thumb ; (</) point of departure of wing 

 membrane from base of toes ; {e) calcaneum or spur ; (/) post-calcaneal lobule and inter- 

 femoral membrane ; {g) degree to which tail projects beyond interfe moral membrane. 



Vespertilio serotinus. The Serotine Bat 



In this species the head and muzzle are particularly flat. The 



front of the face is almost denuded of hair, but there is a slight 



moustache on the upper lip. The thumb has a callosity at its 



base, which is probably the remains of a suctorial disc possessed 



