442 LAND MAMMALS IN THE WESTERN HEMISPHERE 



obscure problems connected with the marine mammals, it may 

 be noted in passing that one of these problems has been brought 

 near to solution, if not actually solved, by the discoveries in 

 Egypt and that is the question concerning the origin of the 

 Sirenia. The order includes the existing Manatee or Sea- 

 Cow (Manatus) of the coast of Florida, northeastern South 

 America and western Africa, and the Dugong (Halicore) of the 

 Indian Ocean. These are mammals which are adapted to a 

 strictly marine habitat and are incapable of existence on land, 

 having lost the hind limbs and converted the fore limbs into 

 swimming paddles. Unlike the whales, porpoises and other 

 Cetacea, the Sirenia are herbivorous and feed upon seaweed 

 and eel-grass and the aquatic plants of large rivers. The 

 Egyptian discoveries tend very strongly to the conclusion that 

 the Sirenia and Proboscidea were both derived from a common 

 stock and that the genus ^Moeritherium was not very far removed 

 from the probable ancestor from which both of the orders 

 descended. 



