occurrence from all parts of Southern Asia and Java
and a great part of Africa. That it belongs to an extremely ancient
genus is testified by the fact of its presence in Mauritius, Japan,
Australia, New Zealand, South America, and Madagascar. The genus
_Bacillus_--to which the typical Stick-insects belong--has a somewhat
similar geographical distribution. But no less than four species of
_Bacillus_ are known from Europe, according to our great authority Mr.
Brunner von Wattenwyl--all from the south; and some of these also range
into North Africa. There are thirty-two other species distributed over
Southern Asia, Africa, Australia, New Zealand, and the Sandwich Islands.

Volumes, indeed, might be filled with lists of species and genera of
terrestrial invertebrates of Oriental origin, but I will not weary the
reader with further enumeration of such instances. Just two more,
however, before concluding, as I have not alluded to the large group of
the _Arachnida_.

Two peculiar spider-like genera, viz., _Galeodes_ and _Rhax_, are found
in Southern Europe. Both occur also in North Africa, and in Western and
a portion of Southern Asia. As the whole family altogether has an
Asiatic character, I cannot agree with Mr. Pocock, who considers them of
European origin and believes that they are migrating eastward.

But not only terrestrial forms migrated to Europe from Western and
Southern Asia. Freshwater species also took part in this great Oriental
migration. I need only refer to the freshwater Crab (_Thelphusa
fluviatilis_), with which Southern Europeans are familiar. It is the
sole representative of a large genus which ranges east as far as
Australia and southward to Madagascar and the Cape of Good Hope. The
European species is found in Turkey, Cyprus, Greece, Southern Italy,
Sicily, North Africa, Southern Spain, Syria, and Persia.

There is a corresponding flora with a range exactly similar to that of
some of the animals quoted. Thus the Balkan Rhododendron (_Rhododendron
ponticum_) is again met with in the western Mediterranean region in
Southern Spain. The Cedar occurs in local varieties in the Himalayan
Mountains, in the Lebanon, and the Atlas Mountains. Both of these are
instances of discontinuous distribution, a proof of their antiquity; but
a large number of plants have a continuous range between Asia Minor and
Spain.

On looking through these few instances of what have been called Oriental
migrants, one cannot help