can be connected only in their far distant beginnings. The
pecoran stock became vastly more expanded and diversified than did
the camel line and was evidently more plastic and adaptable, spreading
eventually over all the continents except Australia, and forming to-day
one of the dominant types of mammals, while the camels are on the
decline and not far from extinction. The Pecora successively ramified
into the deer, antelopes, sheep, goats and oxen, and did not reach
North America till the Miocene, when they were already far advanced in
specialisation. To this invasion of the Pecora, or true ruminants, it
seems probable that the decline and eventual disappearance of the camels
is to be ascribed.

Recent discoveries in Egypt have thrown much light upon a problem which
long baffled the palaeontologist, namely, the origin of the elephants.
(C.W. Andrews, "On the Evolution of the Proboscidea", "Phil. Trans. Roy.
Soc." London, Vol. 196, 1904, page 99.) Early representatives of this
order, Mastodons, had appeared almost simultaneously (in the geological
sense of that word) in the upper Miocene of Europe and North America,
but in neither continent was any more ancient type known which
could plausibly be regarded as ancestral to them. Evidently, these
problematical animals had reached the northern continents by migrating
from some other region, but no one could say where that region lay. The
Eocene and Oligocene beds of the Fayoum show us that the region sought
for is Africa, and that the elephants form just such a series of gradual
modifications as we have found among other hoofed animals. The later
steps of the transformation, by which the mastodons lost their lower
tusks, and their relatively small and simple grinding teeth acquired the
great size and highly complex structure of the true elephants, may be
followed in the uppermost Miocene and Pliocene fossils of India and
southern Europe.

Egypt has also of late furnished some very welcome material which
contributes to the solution of another unsolved problem which had quite
eluded research, the origin of the whales. The toothed-whales may be
traced back in several more or less parallel lines as far as the
lower Miocene, but their predecessors in the Oligocene are still so
incompletely known that safe conclusions can hardly be drawn from
them. In the middle Eocene of Egypt, however, has been found a
small, whale-like animal (Protocetus), which shows what the ancestral
toot