The Mammoth, Wild Boar, Badger, the Dippers and Pheasants, are all Oriental species which have come to us from the south-east; but there are also Reptiles and Amphibians, and a host of Invertebrates. Not all the animals, for instance, which have reached us in England from the south-east are of Asiatic origin. There is an active centre of distribution in South-eastern Europe itself, from which species radiate out in all directions. This fact is well illustrated by the genus Clausilia. Species from this centre, and also from the Alps, joined the Oriental stream in their northward course.
In reviewing a number of instances of Oriental species in Europe, one is struck by the peculiarity of their having apparently followed two distinct routes. All entered from Asia Minor, which is proved to have been connected with Greece until recent geological times. From here some seem to have proceeded straight west, others northward. Further study reveals the fact that the first route was followed by a much older set of migrants at a time when the Mediterranean area was greatly different from what it is at the present day. Greece was then joined to Southern Italy, Sicily, and Tunis. The latter was also connected with Sardinia and Corsica, and the Straits of Gibraltar did not exist. Under such geographical conditions a direct migration on land from Southern Greece to Spain was not only possible, but was actually undertaken by a very large number of Oriental species.
FOOTNOTES:
[1] Since writing the above account, Mr. Boulenger, in his new work on the Batrachia of Europe, has accepted the specific distinctions between the two fire-toads.
[2] In some cases the accuracy of this view is proved by fossil evidence, Helix rotundata, a common and widely spread British species, having been found in miocene strata near Bordeaux.
[3] There are a great many instances of discontinuous distribution among Oriental Invertebrates. Thus the Freshwater Crab (Thelphusa fluviatilis) occurs in Southern Italy, Greece, Turkey, Cyprus, and Asia Minor. Another crustacean—a Freshwater Crayfish—(Hemicaridina Desmaresti) inhabits Spain, Corsica, Sardinia, Sicily, and Asia Minor.
CHAPTER VII.
THE LUSITANIAN FAUNA.
Under the Roman Emperor Augustus, the Spanish peninsula was divided into three provinces, one of which—namely Lusitania—occupied a large portion of the present area of Portugal. The term "Lusitanian" is therefore almost synonymous with Portuguese, but it has frequently been applied by zoologists and botanists in a much wider sense, so as to vaguely include the extreme south-west of Europe without any definite limits. Neither do I propose to restrict the term to everything found within the borders of Portugal. For the sake of convenience, we may designate as Lusitanian forms those animals and plants which have migrated to Central, Southern, or Northern Europe from South-western Europe. They may really be North-west African species, or they may have originated on land which lay to the west of Portugal, and which is now mostly buried beneath a deep sea. Nevertheless, we have received them from the extreme south-western portion of our continent—they have come to greater Europe from that direction.