402 A MANUAL OF DENTAL ANATOMY. 



fox, is an example) have much larger muzzles, and the molar 

 teeth are set with intervals between them. 



212 3 



The dental formula is i - c - p - m -, but in some the 

 2i 1 o o 



molar series is reduced below this number. 



The incisors are small, and the canines rather large. 



Both molars and premolars are of somewhat simple form, 

 being long, and compressed from side to side. The outer 

 borders of the crown of the molars are elevated into distinct 

 but not exceedingly sharp cusps, which become worn down 

 by use. 



The insectivorous character of the presence of many 

 sharp cusps upon the teeth is not to be found in any of the 

 frugivorous bats. All the Pteropi have deciduous canines, 

 and four deciduous molars, of simple pointed form, but the 

 number of deciduous incisors is very variable. 



The milk dentition of bats has been very carefully and 

 thoroughly investigated by Leche (Lund's Universit. Ars- 

 skrift, Tom. XII. and XIV., 1878), and at the present the 

 Megadermata are the only family in which the milk teeth 

 are unknown. The milk teeth are not of much functional 

 importance, as they are shed soon after, if not absorbed 

 before, birth, and they are not therefore implanted in very 

 definite sockets. 



In their slight cylindrical elongated roots, surmounted by 

 expanded crowns, these milk teeth often recall those of the 

 Mole. 



Sometimes the milk teeth are to be found even after the 

 permanent teeth are in situ; in other instances, as for 

 example the deciduous molars of Molossus, they never cut 

 the gum. The milk dentition of the Vampire (Desmodus) ( l ) 



( J ) In a skull of Desmodus, in the possession of Mr. E. F. Tomes, the 

 third milk tooth appears to correspond in position to the permanent 

 canine ; the same is the case in the specimen figured by Messrs. Gervais 

 and Castelmain (Exped. dans les part. cent. d'Amerique du Sud). 



