PRESIDENT'S ADDRESS. 11 



cetaceans are not terrestrial mammals, but marine, and their distri 

 bution is governed by the same laws which affect marine animals 

 generally. The very few peculiar species, except the musk ox, are 

 but little modified relations of forms common to the adjoining 

 realms, and the absence of most forms is evidently dependent on 

 the cold climate, and furnishes no more reason for assigning a pri 

 mary rank to the territory so characterized than it would to the 

 mountain peaks and deserts so frequently isolated in the midst of the 

 adjoining regions, and which are equally distinguished by the 

 paucity of their animal life. The fact that it cannot be distinctly 

 relegated to either the North American or Eurasian realms, but is 

 neutral territory, is scarcely sufficient to warrant its entire isolation 

 from both. 



The next disputed question involves the union or distinction of 

 the Indian and African territories. The question is thus discussed 

 by Mr. Allen. 



INDO-AFRICAN REALM. 



According to Mr. Allen, "The Indo-African Realm consists 

 mainly of Intertropical Africa and Intertropical Asia, to which it 

 seems proper to add Extratropical South Africa. The small por 

 tion of Africa south of the Southern Tropic lies wholly within the 

 warm-temperate zone. Its small extent and broad connection with 

 Tropical Africa render its separation as a distinct realm (as I at 

 one time rather hastily considered it) almost inadmissible, since it 

 is especially open to the influence of the great intertropical African 

 fauna, as is shown by the extension of many tropical forms down to 

 within a few degrees of its southern extremity. The area really 

 possessing a temperate climate is restricted to its extreme southern 

 border, where alone appear the few generic and family types that 

 do not have a very general range over the tropical portions of the 

 continent. This area is many times smaller than the temperate 

 portion of South America, but, though so small, has quite a num 

 ber of peculiar genera, which impart to it quite distinctive features. 

 It yet seems better to regard it as an appendage of the great Indo- 

 African Realm rather than as a distinct primary region. Madagas 

 car, with the Mascarene Islands, on the other hand, while perhaps 

 possessing a closer affinity with Africa than with any other conti- 



