MARINE MAMMALS 211 



towards the tropics the true Seals (Phocirue), which are 

 constituted to live in colder water, gradually fall off in 

 number, and in Mesatlantis are no longer met with. But 

 in their place Ave find the genus Monachus, or Monk-Seal, 

 restricted to Mesatlantis, one species (M. albiventer) occur- 

 ring in the Mediterranean and on the North African coast, 

 and a second (M. tropicalis) being found in the West 

 Indies. Mesatlantis is likewise the true home of the well- 

 marked Sirenian genus Manatus, one species of which (if. 

 americanus) frequents the coast of America and another 

 (M. senegalensis) that of Africa. 



As regards the Cetaceans, we are not at present able to 

 say that Mesatlantis, although well furnished with many 

 generic types of this Order, has any one peculiar to it. 

 We must therefore rest content with assigning two genera 

 of marine mammals, Monachus and Mcmatus, as charac- 

 teristic forms or topomorphs of the Sea-mammal-life of 

 Mesatlantis. 



Section VIII. — The Indian Sea-region, 

 or Indopelagia 



The marine Carnivora, so far as we know, are entirely 

 foreign to Indopelagia, but the Sirenians are well repre- 

 sented by the Dugong (Halicore), which pervades all its 

 northern coasts from North Australia to India and the 

 Eed Sea and down the African coast to the confines of 

 British East Africa. Whether the species of Halicore 

 found at different points within this area are the same 

 or different is still a matter of discussion, but there can 

 be no doubt that Halicore is an exclusive inhabitant of 



