573 



one, have been used by systematists as a distinguishing character. A 

 glance at the synopsis of the genera and species in Dob son's Catalogue 

 of the Chiroptera3 p. 168 and 285 is sufficient to show that. 



And by more modern authors too the dentition, especially the pre- 

 molars, is used as an important character in subdividing the bats into 

 genera. It suffices to mention Winge^ and Gerrit Miller 5, whose 

 classification of the Chiroptera, contained in his work "The families 

 and genera of bats", is the latest classification of those animals „pri- 

 marily based on skeletal and dental characters" (1. c. p. 197). 



I will give only a few instances. According to Dobson (1. c. 

 p. 169 — 170) the genus Scotophilus is in the first place distinguished 

 from its nearest allies by having the first lower premolar small^ crushed 

 in between the canine and second premolar; and the genus Vespertilio 

 [Myotis) is chiefly distinguished from the genus Kerivoula by having 

 the first and second upper premolars much smaller than the third, 

 Kerivoula having the first and second upper premolars nearly equal to 

 the third. 



According to Gr. Miller (1. c.) the genus Pipistrellus differs from 

 the genus Myotis through the absence of pm^ and pms. As regards the 

 genus Eptesicus I can not find any essential difference from the genus 

 Pipistrellus except the number of the premolars, the former genus hav- 



1 



mg pm -. 



Through the kindness of Professor W. Le che, for which I tender 

 him my grateful thanks, I have got an opportunity of examining some 

 groups of bats belonging to the rich collection of Chiroptera of the 

 Zootomical Institute of the University in Stockholm. 



Among the bats belonging to the family Vespertilionidae I 

 have found some cases in which the transition from species to species is 

 manifested in single individuals, the condition of whose premolars clearly 

 shows the connection between forms referred to different genera and 

 which give us an idea of the genesis of those forms. 



As regards the nomenclature of the bats I have used the names 

 accepted by Troëssart in his Catalogus mammalium tam viventium 

 quam fossilium. Quinquen. suppl. 1904. 



The genera Myotis and Pipistrellus differ chiefly with regard to the 

 number of the premolars. Winge says (1. c. p. 35): 



3 Gr. E. Dobson, Catalogue of the Chiroptera in the British Museum. London 

 1878. 



* H. Winge, Jordfundne og nulevende Flagermus (Chiroptera) fra Lage a 

 Santa, Minas Geraes, Brasilien. E. Museo Lundii. Andet Bind. Kjobenhavn 1893. 



5 Gerrit S. Miller, jr., The families and genera of bats. Washington 1907. 



