DEVELOPMENT AND SUCCESSION OF TEETH IN PERAMELES. 4A1 
of our own views we have been largely stimulated and aided by 
Leche’s masterly essay. 
GENERAL ACCOUNT OF THE LEADING CONCLUSIONS FROM OUR 
OWN INVESTIGATION. 
In approaching the subject of our own researches one or 
two matters call for special remark. 
In the first place it is necessary or desirable that we should 
indicate the general grounds upon which we have felt compelled 
to depart from the now usually accepted views of the marsupial 
dentition. The attitude we have felt bound to adopt practi- 
cally implies a return to Winge’s views on the main question 
involved; but with the notable corroboration of that theory 
derived from our interpretation of the so-called ‘ prelacteal”’ 
vestigial teeth as remains of the true milk series, which, 
according to Winge, had been entirely lost from the marsupial 
dentition, except in the case of the deciduous last premolar. 
At the time our research was begun, and for some time 
afterwards, we were fully persuaded of the truth of the 
Kiikenthal-Rése theory, and found no reason to question 
Leche’s identification of his vestigial teeth in Myrmecobius 
as ‘“prelacteal,’ to which category we felt, with Leche, 
strongly disposed to refer the vestigial calcified teeth dis- 
covered by Woodward in the Macropodide. 
We were accordingly highly delighted to (apparently) con- 
firm the accepted views by the further discovery in Pera- 
meles of a number of quite similar “ prelacteal”? rudimentary 
teeth. 
The examination of the earlier stages of tooth development 
in Perameles, however, forced upon us irresistibly the con- 
viction that the deciduous premolar in that animal 
must belong to the same series as the so-called 
* prelacteals.” 
For in Perameles the deciduous premolar is differentiated 
from the dental lamina contemporaneously with the so-called 
 prelacteal”’ teeth, and at a period prior to the differentiation 
