s are branches in
different directions from this stem.

What the _Protamniota_ were like, I do not suppose any one is in a
position to say, but I cannot think that the thoroughly Lacertian
_Protorosaurus_ had anything to do with them. The reptiles which are
most amphibian in their characters, and therefore, probably, most
nearly approach the _Protamniota_, are the _Ichthyosauria_ and the
_Chelonia_.

That the _Didelphia_ were developed out of some ornithodelphous form,
as Professor Haeckel supposes, seems to be unquestionable; but the
existing Opossums and Kangaroos are certainly extremely modified and
remote from their ancestors the "_Prodidelphia_," of which we have
not, at present the slightest knowledge. The mode of origin of the
_Monodelphia_ from these is a very difficult problem, for the most
part left open by Professor Haeckel. He considers the _Prosimiae_, or
Lemurs, to be the common stock of the _Deciduata_, and the _Cetacea_
(with which he includes the _Sirenia_) to be modified _Ungulata_. As
regards the latter question, I have little doubt that the _Sirenia_
connect the _Ungulata_ with the _Proboscidea_; and none, that the
_Cetacea_ are extremely modified _Carnivora_. The passage between the
Seals and the _Cetacea_ by _Zeuglodon_ is complete. I also think
that there is much to be said for the opinion, that the _Insectivora_
represent the common stock of the _Primates_ (which passed into
them by the _Prosimiae_), the _Cheiroptera_, the _Rodentia_, and the
_Carnivora_. And I am greatly disposed to look for the common root
of all the _Ungulata_, as well, in some ancient non-deciduate Mammals
which were more like _Insectivora_ than anything else. On the other
hand, the _Edentata_ appear to form a series by themselves.

The latter part of this notice of the _Natuerliche
Schoepfungs-Geschichte_, brings so strongly into prominence the points
of difference between its able author and myself, that I do not like
to conclude without reminding the reader of my entire concurrence with
the general tenor and spirit of the work, and of my high estimate of
its value.

XII.

BISHOP BERKELEY ON THE METAPHYSICS OF SENSATION.[1]

Professor Fraser has earned the thanks of all students of philosophy
for the conscientious labour which he has bestowed upon his new
edition of the works of Berkeley; in which, for the first time, we
find collected together every thought which can be traced to the
subtle and penetrating