86 BRITISH MAMMALS 



by other species of bats attached to the base of the thumb or the 

 soles of the feet, and enabling them to adhere more tightly to 

 smooth surfaces over which they are creeping. The use of this 

 disc has evidently been lost in the Serotine Bat, but its rudiment 

 remains. The upper incisor teeth of all old specimens betray 

 a tendency to divide in two at the extremity. They are marked 

 with a groove even when this has not deepened into division. 

 The lower incisors betray a similar tendency to split into three 

 points. There are two pairs of incisors in the upper jaw and 

 three in the lower, one pair of canines in both jaws, one pair 

 of premolars above and two pairs below, and three pairs of molars 

 in each jaw. The length of the head and body is about i\ in. 

 the tail measuring 2 in. more. As regards colour, this bat is 

 generally a dark brown, paling to yellow-brown or yellowish-gray 

 on the under parts. The wing membrane, of course, as in all 

 British bats, is a dark sepia or blackish-gray. The serotine bat 

 produces a single young one at a birth, this event taking place 

 about the month of June. In the British Islands its distribution 

 seems to be confined to a small portion of the south of England 

 between Cornwall and Essex. Outside England its range is so 

 world-wide as to exceed that of any other bat, for it is found 

 over all Temperate Europe, Asia, and North America, also in 

 North Africa, and even, it is said, in parts of South America. 

 It has been named the " serotine " bat from its habit of only 

 making its appearance late in the evening, and not at sunset. 

 It is not as gregarious in its habits as other members of the 

 genus, and is accustomed to hibernate singly, taking up its 

 abode in hollow trees. 



A species allied to the serotine is the Parti-coloured Bat 

 (Vesper tilio murinus). This bat has the colour of the upper parts 

 dark brown, spangled with yellowish-white, owing to the last 

 quarter of the long hairs being that colour. The under parts are 

 yellowish-white, with gray as an under colour. In the middle of 

 the chest and stomach there is a large patch of reddish-brown 

 flecked with white. It is about the size of the serotine bat — 

 perhaps a little smaller — with a tail proportionately somewhat 



