380 BULLETIN OF THE 



of life in a given area and the relative temperature of that area, the 

 number of distinct forms increasing directly with the increase in the 

 temperature, other conditions remaining essentially unchanged. The 

 number of distinct species and geographical races also increases directly 

 with the increase in the diversity of the conditions of life resulting 

 from differences of geographical configuration. Hence fauna? and 

 flora? cover a smaller area in the warm temperate and tropical latitudes 

 than at the northward, and in a mountainous region than in a level 

 region. Hence within the torrid zone, where a maximum temperature 

 is generally associated with a highly diversified surface, species, genera, 

 and families are the most numerous, and faunae and flora?, as well as 

 species, are ordinarily the most narrowly circumscribed. 



In accordance with the facts stated above respecting the mode of 

 the distribution of animals and plants over the earth's surface, and the 

 zoological and botanical laws of the differentiation and mutual relations 

 of the different regions, the following primary natural-history divisions 

 may be recognized : I, an Arctic Realm ; II, a North Temperate 

 Realm ; III, an American * Tropical Realm ; IV, an Indo-African 

 Tropical Realm; V, a South American Temperate Realm; VI, an 

 African Temperate Realm ; VII, an Antarctic Realm ; VIII, an Aus- 

 tralian Realm. 



The Arctic Realm presents a nearly uniform character throughout 

 its extent, and, though embracing several faunae, is not divisible into 



* The terms " Palir-ogean " and " Neogean," " Pala?arctic " and ' Nearctie " etc., like 

 those of " Old World " and " New World," have been given with reference solely to the 

 length of time the different land areas of the earth's surface have been known to the 

 dominant race of mankind, and hence regardless of the zoological history of these 

 different land areas. Modem science has taught us that the latent discovered continent 

 (Australia) is peopled with the most ancient types of animals and plants now in exist- 

 ence, and that it is, zoologically considered, the ancient continent. Also that North 

 and South America are behind Europe, Asia, and Africa in their zoological and 

 geological development, while they are far in advance of Australia. To apply the 

 term "ancient" to what is really the most recent, and "modern" to what is mediaeval, 

 is evidently too great a misuse of language to be allowable in scientific nomenclature. 

 The sciences of geographical zoology and geographical botany concern not merely 

 the geographical distribution of the animals and plants now living, hut also those of the 

 pa t. If such descriptive terms as the a hove are to be employed, it is evidently im- 

 portant that they should he used in their legitimate sen<e. In the present paper it has 

 hence been considered advisable to altogether discard these terms, since to use them 

 properly woidd nece-dtate their adoption in a manner directly opposite to their origma' 

 and generally accepted application. 



