264 



MAMMALIAN DENTITION 



case of the human dentition. We must therefore consider the 

 matter in a little more detail. 



Not only do the cheek teeth of the Aye-aye possess relatively 

 short roots fused in part of their extent, but this fusion, least 

 marked in the first molar, involves progressively more of the 

 roots in the second and most in the third. This is natural 

 since, as we have frequently observed, it is the first molar 

 which is the most stable. Again the pulp chamber of all three 



Fig. 97. — Skiagram of jaws of Aye-aye (Daubentonia madagascariens's, 9.815-1). 

 Note the short roots fused in part of their length especially in the third molar, and 

 the large pulp chamber the outline of which sinks benea'h the level of the alveolar 

 border of the jaw. 



molars but more especially of the third is relatively long and 

 tends to sink beneath the level of the alveolar border of the 

 jaw.* This is a marked distinction from the appearance pre- 



*It is true that the pulp chamber diminishes in size with age through the appear- 

 ance of secondary dentine, and that in consequence the skiagram of the jaws of a young 

 animal will show a larger pulp chamber in the third molar than in the first, because 

 the latter erupted long before the former. Any fallacy in interpretation of Fig. 97 

 upon this score is precluded by the fact that the specimen is an old one. The inter- 

 pretation given is further indicated correct by the progressive fusion of the roots 

 backward in the molar series. 



