in the Oriental and Ethiopian Regions, are likewise found in the Palearctic Region. Furthermore, out of the eight genera above mentioned, although they are not now found in the Palearctic Region, four of them are known to have existed there during the Pliocene period. This shows, we think, very conclusively that what small resemblance there is between the mammals of the Oriental and Ethiopian Regions is due rather to a similarity in their origin, than to any sort of direct connection between the two regions. To sum up the subject we add a table of the numbers of orders, families, and genera of mammals found in the six different Regions, together with the number of genera confined to them (endemic), the number of those slightly transgressing the Regional borders (quasi-endemic), and the number of those of wide-spread distribution in each Region. In the second table these numbers have been reduced to percentages, which give in some respects a better idea of the relative specialisation of the mammalfauna of each Region. On examining these tables, it will be seen that the Ethiopian Region stands second in point of the number of genera confined to it, coming next to the Neotropical Region. The lists of genera from which this table has been worked out are based on those adopted in Flower and Lydekker's (3) standard work on mammals, with a certain number of additions and corrections. In consequence of this the figures in the case of the Nearctic Region will not be found to exactly correspond with those quoted from Mr. Allen above (2). It must also, of course, be understood that the figures are merely approximate, and liable to continual alterations as new discoveries are made. TABLE I. Approximate Numbers of Families, Genera, and Species of Numbers given in Table I. reduced to Percentages of Total The groups entirely confined to each region are classed as "endemic"; those that cross the frontiers slightly as "quasi-endemic "; all others are considered as "wide-spread." The percentages, it will be observed, on account of the omission of fractions, do not exactly make up one hundred in every case. 17 LIST OF THE PRINCIPAL AUTHORITIES REFERRED TO IN CHAPTER I. (1) ALLEN, J. A.-"The Geographical Distribution of Mammals." Bull. U.S. Geol. Surv. IV., p. 376 (1878). (2) "The Geographical Distribution of North American Mammals." Bull. Amer. Mus. Nat. Hist. IV., p. 199 (1892). (3) FLOWER, W. H., and LYDEKKER, R.-"An Introduction to the Study of Mammals, Living and Extinct." London (1891). (4) GILL, T.-"The Principles of Zoo-Geography." Proc. Biol. Soc. Washington, II., p. 1 (1885). (5) HEILPRIN, A.-"The Geographical and Geological Distribution of Animals." London (1887). (6) HUXLEY, T. H.-"On the Classification and Distribution of the Alectoromorphæ and Heteromorpha." Proc. Zool. Soc., 1868, p. 294. (7) NEWTON, A.-Article on Geographical Distribution in the "Dictionary of Birds," p. 311. London (1893). (8) SALVADORI, T.-"Catalogue of the Psittaci or Parrots in the Collection of the British Museum." London (1891). (9) SCLATER, P. L.-" On the General Geographical Distribution of the Members of the Class Aves." Journ. Proc. Linn. Soc. (Zool.), vol. ii., p. 130 (1858). (10) Address to Section D. (Biology). "Report of the FortyFifth Meeting of the British Association at Bristol,” p. 85 (1876). (11) "On the recent Advances in our Knowledge of the Geographical Distribution of Birds." Ibis (6), vol. iii., p. 514 (1891). (12) SHARPE, R. B.-"On the Zoo-Geographical Areas of the World." Nat. Science III., p. 100 (1893). (13) WALLACE, A. R.-"The Geographical Distribution of Animals." 2 vols. London (1876). B |