THE LIFE OF MAMMALS 
placental method of reproduction, although an advance upon 
the egg laying of the monotremes. Upon it was based the 
former separation of the marsupials as a subclass Mctatheria, 
of equal rank with the Eu‘heria or higher mammals, on the one 
hand, and with the Prototheria or monotremes on the other. 
Since it has been found that in the bandicoots (Perameles) 
there exists a true allantoic placenta, this distinction breaks 
down, and naturalists are forced to the conclusion that instead 
of being an independent primitive stock, the marsupials “have 
sprung from a stock with an allantoic placenta,” — that is to 
say, its origin was the same as that of all other groups of mam- 
mals except (as it now appears) the monotremes. When the 
divergence in the methods of reproduction began, paleontology 
gives little indication. It is a noteworthy fact that now the 
pouch is least perfect (occasionally absent) in those forms which 
are of most ancient and general type. 
Very characteristic of the group are the presence of two detached bones 
in the epipubic region; and also the fact that the hinder extremity of the 
lower jaw is always bent inward, or “inflected,” —a reptilelike feature 
of much weight in determining the affinities of the earlier fossil remains, 
which so often consist of only a half of a lower jaw. The brain of all mar- 
supials is ‘very small in proportion to the size of the head and body, while 
its external surface exhibits comparatively few foldings and convolutions, 
thus indicating that the brain power and general intelligence of these 
creatures are of a low grade.” The experience of hunters and also of those 
who have made pets of many species, and found them gentle, amusing, and 
quick to learn, does not bear out this deduction. Doubtless, the mar- 
supials, like other animals, have quite as much intelligence as their several 
circumstances require. Many clever acts have been reported of them. 
Nevertheless, the type of brain, the character of the dentition and other 
features detailed by Parker and Haswell,” Beddard,®” Lydekker,”* and other 
specialists, show that the marsupials must be placed near the foot of the 
list in respect to organization. 
Many of the earliest mammals of which we have any certain 
information were of this race, and such were all of that division 
(polyprotodont) represented by the bandicoots. As far down in 
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