The majority of the European Reptiles are probably of eastern origin. Among our British species, the Common Viper (_Pelias berus_), for example, is a typically eastern form. It is almost unknown in Southern Europe proper--that is to say, in Italy, the Balkan peninsula, and the Mediterranean Islands, but its range extends in the west as far as Spain, and in the east right across the Asiatic continent to Japan. It is well known that the Viper occurs in Scotland, and that neither it nor any other snake is found in Ireland. There is a legend, indeed, that snakes did once exist in Ireland and were banished from the island by St. Patrick, but unfortunately we have no historical evidence that such an interesting event actually took place. The Sand-Lizard (_Lacerta agilis_), another British species, may be looked upon as an eastern form. It is quite absent from Italy, the Balkan peninsula, and the Mediterranean Islands, but extends throughout Central Europe to the east. Among the species of eastern Reptiles which have a mere local range in Europe might be mentioned the two Lizards, _Phrynocephalus auritus_ and _Agama sanguinolenta_. They belong to the family _Iguanidæ_, which includes some very large species. Both of them are Asiatic forms, which have only just penetrated across the eastern steppes into Europe, where they inhabit the arid regions between the Caspian and the River Don in Southern Russia. The species of Mammals living in Europe at the present day have, with few exceptions, migrated to our continent from other parts of the world. With regard to the Birds, it is possible that a somewhat larger number proportionally may be of European origin. Still, the great majority are, I think, to be regarded as immigrants. The autochthones are about equal to the immigrant reptiles, but many of the European Amphibians and the majority of the Fishes have probably originated on our continent. Some of the European Amphibia--especially among the tailless forms--appear to be immigrants from Asia. Thus the distribution of _Rana arvalis_ in Europe is remarkably like that of a Siberian migrant. This frog occurs in Siberia, ranging southward as far as Persia and parts of Asia Minor. Crossing the European border, we find it in Russia, Upper Hungary, North and Central Germany,--being rarer in the south,--Denmark, and Scandinavia. According to Bedriaga, it crosses the Rhine only in Alsace, but occurs no farther west. It only just enters Holland. If we suppose the species to have originated in Central Europe, we should expect to find it in Switzerland, France, and perhaps England. If it had its ancestral home in Eastern Europe, we might expect it to occur on the Balkan peninsula. It seems to me more probable, therefore, that _Rana arvalis_ came with the Siberian migration. This need not cause surprise, as the genus _Rana_ is certainly not European. Out of about 110 species, only four are peculiar to Europe, the rest are scattered over all parts of the globe.