ON THE SUCCESSION AND GENESIS OF 

 MAMMALIAN TEETH. 



1^ H E form and relations of the teeth have always occu- 

 pied a prominent place among those characters which 

 determine the systematic position and individual peculiarities 

 of any mammal. And when we consider that owing to its com- 

 position a tooth is one of the most resistant structures which 

 these animals possess, it will at once be evident that the 

 importance of the teeth cannot be overestimated in relation 

 to the study of the past history of the group as determined 

 from their fossil remains. We cannot therefore investigate 

 too carefully the many doubtful points in tooth relationships, 

 the solving of which may assist us in obtaining a more com- 

 plete knowledge both of the inter-relationships of the different 

 orders of mammalia and of the ancestry of the mammalian 

 phylum itself. 



The study of comparative odontology is a very old one, 

 but it is not until we come to the beginning of the present 

 century that we find any very comprehensive attempt to 

 treat this subject in a systematic way. Such an attempt 

 we owe to F. Cuvier (i), who was one of the first to give 

 us any detailed description of the teeth of a large number 

 of mammals and to endeavour to homologise the same. 



Following closely upon Cuvier we find Owen (2, 3, 4, 5) 

 in this country working at the same subject, and it is from 

 his numerous memoirs that the science of comparative 

 odontology may be said to have arisen. On comparing 

 his results with those of more recent investigators, it is 

 astonishing to find how very little our latest conclusions 

 differ from those at which he arrived as early as 1868, 

 especially when we consider the advances which have been 

 made in the methods of observation. 



His introduction (5) of a systematic method of express- 

 ing the dentition of a mammal by means of symbols 

 has been of immense use to comparative anatomists, al- 

 though the use of these dental formulae may be in some 

 instances carried too far, considering that they may only 



