INTRODUCTION. 



THIS volume is devoted to the consideration of a 

 group of quadrupeds or Mammalia, most of the 

 species of which are commonly known either by the 

 name of Opossum or Kangaroo. The first discovered 

 species of this group were found in America, and are 

 described by the earlier English authors, under the 

 former of these names ; subsequently other animals 

 were found in certain islands of the Indian Archi- 

 pelago, and in Australia, which having some charac- 

 ters in common with the Oppossums of America, 

 were placed in the same group, and described under 

 the original title of Didelphis* given by Linnseus to 

 the American Opossum. This name was suggested 

 by one of the most remarkable characters which these 

 animals exhibit, viz. : the possession, in the female, 

 of a pouch or fold of skin on the abdomen, in which 

 the young are carried. 



The term marsupiata, or marsupialia, (from 

 marsupium, a purse or bag,) now usually applied to 



* From A/ and Asxpvj, double uterus, should therefore be 

 Didelphys. 



