_General Conclusions as to the Fauna of the Palæarctic Region._--From the account that has now been given of the fauna {232}of the Palæarctic region, it is evident that it owes many of its deficiencies and some of its peculiarities to the influence of the Glacial epoch, combined with those important changes of physical geography which accompanied or preceded it. The elevation of the old Sarahan sea and the complete formation of the Mediterranean, are the most important of these changes in the western portion of the region. In the centre, a wide arm of the Arctic Ocean extended southward from the Gulf of Obi to the Aral and the Caspian, dividing northern Europe and Asia. At this time our European and Siberian sub-regions were probably more distinct than they are now, their complete fusion having been effected since the Glacial epoch. As we know that the Himalayas have greatly increased in altitude during the Tertiary period, it is not impossible that during the Miocene and Pliocene epochs the vast plateau of Central Asia was much less elevated and less completely cut off from the influence of rain-bearing winds. It might then have been far more fertile, and have supported a rich and varied animal population, a few relics of which we see in the Thibetan antelopes, yaks, and wild horses. The influence of yet earlier changes of physical geography, and the relations of the Palæarctic to the tropical regions immediately south of it, will be better understood when we have examined and discussed the faunas of the Ethiopian and Oriental regions. {233}TABLES OF DISTRIBUTION. In constructing these tables showing the distribution of various classes of animals in the Palæarctic region, the following sources of information have been chiefly relied on, in addition to the general treatises, monographs, and catalogues used in compiling the fourth part of this work. _Mammalia._--Lord Clement's Mammalia and Reptiles of Europe; Siebold's Fauna Japonica; Père David's List of Mammalia of North China and Thibet; Swinhoe's Chinese Mammalia; Radde's List of Mammalia of South-Eastern Siberia; Canon Tristram's Lists for Sahara and Palestine; Papers by Professor Milne-Edwards, Mr. Blanford, Mr. Sclater, and the local lists given by Mr. A. Murray in the Appendix to his Geographical Distribution of Mammalia. _Birds._--Blasius' List of Birds of Europe; Godman, On Birds of Azores, Madeira, and Canaries; Middendorf, for Siberia; Père David and Mr. Swinhoe, for China and Mongolia; Homeyer, for East Siberia; Mr. Blanford, for Persia and the high Himalayas; Mr. Elwes's paper on the Distribution of Asiatic Birds; Canon Tristram, for the Sahara and Palestine; Professor Newton, for Iceland and Greenland; Mr. Dresser, for Scandinavia; and numerous papers and notes in the Ibis; Journal für Ornithologie; Annals and Mag. of Nat. History; and Proceedings of the Zoological Society. _Reptiles and Amphibia._--Schreiber's European Herpetology. {234}TABLE I.