CHAPTER IV.

ON ZOOLOGICAL REGIONS.

Principles upon which Zoological Regions should be formed (p. 53)--Which class of Animals is of most importance in determining Zoological Regions (p. 56)--Various Zoological Regions proposed since 1857 (p. 58)-- Discussion of proposed Regions (p. 61)--Reasons for adopting the Six Regions first proposed by Mr. Sclater (p. 63)--Objections to the system of Circumpolar Zones (p. 67)--Does the Arctic Fauna characterise an independent Region (p. 68)--Palæarctic Region (p. 71)--Ethiopian Region (p. 73)--Oriental Region (p. 75)--Australian Region (p. 77)--Neotropical Region (p. 78)--Nearctic Region (p. 79)--Observations on the series of Sub-regions (p. 80) 50-82