THE ANNALS 



AlTD 



MAGAZINE OF NATURAL HISTOEY. 



[SIXTH SERIES.] 

 No. 38. FEBRUARY 1891. 



XIX. — On the Adaptation of Mammals to Aquatic Life. 

 By Dr. Willy Kukenthal, Ritter-Professor of Phjlo- 

 geny in the University of Jena *. 



The organization of the mammal is fitted for the life on dry 

 land, just as that of the fish and the bird is adapted to an 

 existence, in the one case in the water, in the other in the air ; 

 and we can form a good idea of the intensity of the struggle 

 for existence when we observe how large a number of mammal 

 has been driven from the surface of the land. The majority 

 of the orders belonging to this class contain representatives 

 which have adopted either a burrowing subterranean, an aerial, 

 or an aquatic mode of life. The latter especially is of frequent 

 occurrence, and we see how entire orders of mammals, such as 

 the Whales, the Sirenians, and the Seals, have been driven 

 into the water. Orders too, otherwise terrestrial, contain 

 solitary representatives which have abandoned the terrestrial 

 life, such as Plafi/jjus among the Monotremata and Chiro- 

 nectes variegatus among the Marsupialia, while among the 

 Rodents we have a larger number : — 



* Translated from the ' Zoologische Jabi-biicber,' Abtbeiliing fiirSyste- 

 niatik, Geotrrapbie, unci liiologio' der Tbiere, Bd. v. Heft 3, Jena, October 

 la'JO, pp. 373-a7'J. 



Ann. (k Mag. N. Hist, Ser. 6. Vol. vii. 11 



