194 The Palaeontological Record. I. Animals 
America until a very late period. Interesting side-branches of this 
line have also been found, one of which ended in the upper Miocene 
in animals which had almost the proportions of the giraffes and must 
have resembled them in appearance. 
The American Tertiary has yielded several other groups of 
ruminant-like animals, some of which form beautifully complete 
evolutionary series, but space forbids more than this passing mention 
of them. 
It was in Europe that the Artiodactyla had their principal 
development, and the upper Eocene, Oligocene and Miocene are 
crowded with such an overwhelming number and variety of forms 
that it is hardly possible to marshal them in orderly array and 
determine their mutual relationships. Yet in this chaotic exuberance 
of life, certain important facts stand out clearly, among these none is 
of greater interest and importance than the genealogy of the true 
Ruminants, or Pecora, which may be traced from the upper Eocene 
onward. The steps of modification and change are very similar to 
those through which the camel phylum passed in North America, 
but it is instructive to note that, despite their many resemblances, 
the two series 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’. 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 
10, W. Andrews, “On the Evolution of the Proboscidea,” Phil. Trans. Roy. Soc. 
London, Vol. 196, 1904, p. 99. 
