CHIROPTERA 



II 



by the following table, from which it will be seen that, as 

 regards size, they fall into two groups, viz., three large bats — 

 the Noctule, Serotine, and Greater Horseshoe — in which 

 the forearm measures about 50 mm,, and the remainder, 

 with a forearm varying between 30 and 42 mm. Leisler's and 

 Bechstein's are the largest, and the Pipistrelle is the smallest of 

 the latter group. 



i^o(e.— The square brackets indicate that the enclosed figures are based on measurements of less 



than five specimens. 



In order to compare the proportions of the species, the 

 dimensions have in a second table been reduced to terms of 

 their respective forearms, the reason for selecting the forearm 

 being that it is probably the most stable feature of the wing. 

 Thus in the eleven British bats (omitting Bechstein's, for 

 which no series is available), the forearm bears the fairly 



