CHAPTER XVII.

THE DISTRIBUTION OF FRESHWATER FISHES 208

List of Freshwater Fishes, 208--Continuous and interrupted range of distribution, 209--The ways of dispersal of Freshwater fishes, 211--A wide range of a type is not necessarily proof of its antiquity, 212--Each fauna is composed of ancient, autochthont, and immigrant species, 213--Division of the globe into zoological regions; freshwater fishes have been spread in circumpolar zones, 215--Cyprinidæ and Siluridæ, most important families in recognising the zoo-geographical regions, 216--Division of the faunæ of Freshwater fishes, 217--I. Equatorial Zone, 218--Indian Region, 220--African Region, 227--Tropical American or Neotropical Region, 233--Tropical Pacific Region, 238--II. Northern Zone, 240--Europe-Asiatic or Palæarctic Region, 243--North American or Nearctic Region, 246--III. Southern Zone, with Tasmanian, New Zealand, and Fuegian Sub-regions, 248.