On the other hand, there are those who believe that the functional dentition (other than the replacing premolar and the molars) correspond to the milk-dentition of placentals, and that the rudimentary tooth-germs represent a "prelacteal" dentition.
Owing to the antiquity of both placentals and marsupials, the arboreal character of the feet of the modern forms of the latter is of little importance.
Finally, there is the hypothesis that marsupials are the descendants of placentals, in which case, as was suggested by its discoverer, the placenta of the bandicoots would be a true vestigial structure.
Other distinctive features by which marsupials are separated from monodelphians or placentals will be found in the article last mentioned.
On the assumption that these functional teeth correspond to the milk-series of placentals, "marsupials in this respect agree exactly with modern elephants, in which the same peculiarity exists.