DEVELOPMENT AND SUCCESSION OF TEETH IN PERAMELES. 427 
Observations upon the Development and Suc- 
cession of the Teeth in Perameles; together 
with a Contribution to the Discussion of 
the Homologies of the Teeth in Marsupial 
Animals. 
By 
J. T. Wilson, M.B., 
Professor of Anatomy, 
and 
4 
J. P. Hill, F.LS., 
Demonstrator of Biology in the University of Sydney, New South Wales. 
With Plates 25—32. 
Part I.—IntrRopvuction. 
REcENT years have witnessed a noteworthy revivai of interest 
in the morphological interpretation of the facts of mammalian 
dentition. This renewed interest is traceable to the more 
systematic and thorough-going application of the methods of 
embryological study to the distinctively morphological, and no 
longer merely to the histogenetic aspects of the phenomena of 
tooth development. These methods have yielded a valuable 
supplement to the work of the systematist and paleontologist, 
and have provided a very necessary basis for a critical estimate 
of views arrived at by investigators working along such dif- 
ferent lines of research. 
As a result of the fresh activity to which we have alluded 
there has sprung up a pretty copious literature, which, added 
to that previously existing, renders the study of the problems 
of dentition at the present day by no means a light one, 
