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410 GEOGRAPHICAL ZOOLOGY. [part iv.
RemarTcs on the Distribution of the Chelonia.
The four families into which the Chelonia are classed have
all of them a wide distribution, though none are universal.
The Ethiopian region seems to be the richest, as it possesses 3
of the four families, while no other region has more than 2 ;
and it also possesses 7 peculiar genera. Next comes the Neo-
tropical region with 2 families and 6 peculiar genera ; the
Australian with 3, and the Nearctic with 2 peculiar genera;
while the Oriental and Palsearctic regions possess none that
are peculiar. There are about 30 genera and 200 species
in the whole order.
Fossil Chelonia.—The earliest undoubted remains of this order
occur in the Upper Oolite. These belong to the Cheloniidse
and Emydidse, which are also found in the Chalk. In the
Tertiary beds Chelonia are more abundant, and the Trionychidse
now appear. The Testudinidse are first met with in the Miocene
formation of Europe and the Eocene of North America, the
most remarkable being the gigantic Golossochelys Atlas of the
Siwalik Hills. It appears, therefore, that the families of the
order Chelonia were already specialised in the Secondary period,
a fact which, together with their more or less aquatic habits,
sufficiently accounts for their generally wide distribution.
Species of Testudo, Emps, and Trionyx, are found in the Upper
Miocene of the south of France. .