CHAPTER XVI 



THE BATS 



General position of the order — Megachiroptera and Micro- 

 chiroptera — Vespertilio fuscus — Importance of the incisor 

 specialization — Molars of the Fruit Bats. 



The Chiroptera or Bats possess a very long history having 

 been highly specialized even in Eocene times. Their anatomy 

 however reveals the probability that they originated from prim- 

 itive arboreal Insectivores perhaps of the Cretaceous, perhaps 

 of the Basal Eocene. Their dental formula is derived by re- 

 duction from the primitive Placental type. There are two 

 groups of Bats, the Megachiroptera or Fruit Bats and the 

 Microchiroptera or insectivorous Bats, the latter being 

 the more specialized in their general anatomy. But just as 

 the Walrus though generally less specialized than the Seals 

 yet has a dentition more aberrant, so also the Fruit Bats gen- 

 erally less removed than the insectivorous Bats from typical 

 Insectivores, present a dentition in which it is much more dif- 

 ficult to trace homologies. The link connecting the Fruit Bats 

 with the Insectivores proper is the so-called Flying Lemur, 

 Galeopithecus. 



For the purpose of this volume it will be sufficient to glance 

 at the dentition of one of the Microchiroptera, the more special- 

 ized group. We have therefore figured the skull of the common 

 Brown Bat, Vespertilio fuscus (Fig. 82). The number of in- 

 cisors and cheek teeth differs greatly among the Bats but in 

 V. fuscus the formula is: 



1 1, Ct,P + m4- total 32. 

 ,3 1 5 



230 



