56 



Ethiopian,* the Sirenian mammalia ; Struthious birds ; Elapid aud Pero- 

 _podows snalies ; Bipnoan, Chromid, and Characin &shes ; aud Pleurodire 

 tortoises, are universal, and not, or very sparsely, found in the northern. 

 Of other groups peculiar to the Southern or Equatorial regions, the 

 Edentate mammalia belong to the Neotropical and Ethiopian ; the Osteo- 

 glossid fishes to the Neotropical, Palaeotropical, and Australian ; while 

 monkeys occur in the southern faunae, except the Australian, and in 

 the Palaeotropical. The Ethiopian shares many peculiarities with the 

 Northern. Thus, Insectivorous mammals, Viperine snakes, and Eani- 

 form frogs, are only found here in the southern hemisphere. 



The Neotropical realm only possesses exclusively the Platyrhine mon- 

 keys and the great majority of the humming-birds. It shares with 

 other Southern regions the Edentate and Tapiroid mammals; Struthi- 

 ous, Pullastrine, and Clamatorial birds; Elapid snakes; Arciferous 

 frogs; and Characin, Chromid, Osteoglossid, and Dipnoan fishes. It 

 has but few types of the Northern regions ; these are numerous pleuro- 

 dont Lacertilia, the Acrodonts being entirely absent ; and a few bears, 

 deer, and Oscine birds. 



The Ethiopian realm is that one which combines the prevalent features 

 of the Palaearctic region with the southern-hemisphere tyi)es already 

 mentioned, together with some found elsewhere only in the Palaeotrop- 

 ical, and a very few peculiar. The two latter classes not being men- 

 tioned elsewhere, they maj' be here enumerated. This region shares, 

 with the Indian alone, the Oatarrhine monkeys, the Elephantidae Bhi- 

 nocerotidae, and Chamaeleons. Its peculiar types are the Lemuridae, 

 Hippopotamidae, and Cameleopardalidae, among mammals, aud Polypter- 

 idae and Mormyridae among fishes. 



The Northern realms of the earth agree in possessing all the earless 

 seals ; but most of its common characters are shared by India and 

 Africa. With these regions they possess most all of the Knminant and 

 Insectivorous mammals, and all the Eaniform frogs. The Palaearctic 

 and Palaeotropical are very much alike, and ought probably to be 

 united. The latter differs in possessing monkeys, elephant, rhinoceros, 

 and tapir, Elapid serpents (cobras), and Osteoglossid fishes. In other 

 respects, as in mammalia generally, Oscine birds and fresh-water fishes, 

 and reptiles generally, it agrees with Northern Asia and Europe. 



The Nearctic or North American realm is that with which we have 

 here to do. It extends from the Arctic regions to a line drawn across 

 Northern Mexico, and includes the peninsula of Lower California. It 



'"Eogaea" of Gill, characterized in his article "On the geographical distribution of 

 Fishes", in the "Annals and Magazine of Natural History- ' (4), xv, 255. 



