444 J. T. WILSON AND J. P. HILL. 
have occasion to notice, there are abundant remains in 
Perameles. 
We are convinced that this view is amply justified by the 
considerations set forth in this paper, and that, when 
deliberately weighed, it will at once be found agreeable to all 
the facts of development of the marsupial dentition, and to 
afford a far more natural and unstrained explanation of these 
facts than the hypotheses heretofore dominant. We cannot 
but believe that the enormous simplification which would be 
effected by the adoption (if satisfactorily demonstrated) of the 
view we now advocate must be appreciated on every hand. In 
its light the peculiarities of the marsupial dentition may be 
rendered easily intelligible, and the difficulties of interpreta- 
tion hitherto associated with these peculiarities forthwith 
disappear. 
In particular the new view would seem to afford the only 
adequate explanation of Rése’s highly interesting discoveries 
in the wombat. We have already seen how this observer felt 
bound to interpret the rudimentary teeth he found in his 
foetal specimen as belonging to a milk series; and although 
Schwalbe and Leche have both subsequently expressed the 
opinion that these rudiments are to be interpreted as ‘‘ pre- 
lacteal,’’? we are of opinion that this view presents many 
difficulties which are obviated by the simpler and more natural 
view we feel bound to advocate on the grounds of our own 
observations. We at least find it now impossible to adopt any 
different conclusions on the points in question, respecting the 
morphology of the marsupial dentition, than the following : 
1. The permanent teeth of Marsupials are the homologues 
of the permanent or replacing teeth of higher mammals. 
2. The deciduous premolar is a true milk-tooth, and it is 
not the sole representative of the series to which it belongs, 
since the so-called ‘‘ prelacteal ” teeth are in reality milk-teeth 
which have undergone reduction, and have well-nigh wholly 
disappeared, under the operation of influences unfavorable to 
their development. 
3. The lingually situated downgrowths of the dental lamina 
