48 INTRODUCTION. 



been published Anatomists have aided the Zoologist 

 in determining the relations of the Marsupial animals 

 to other orders of Mammalia, and their affinities with 

 each other; among others may be mentioned John 

 Hunter, Sir E. Home, Geoffroy Saint-Hilaire, G. 

 Cuvier, Meckel, De Blainville, Morgan, Owen, 

 Martin and Laurent. 



It has been stated that the first discovered species 

 of Marsupiata were those of America, and that sub- 

 sequently species have been found in Australia, and 

 in some of the islands of the Indian Archipelago : 

 it must be observed, however, that Australia is the 

 great metropolis of these animals ; in America 

 there exists many species, but they all belong to 

 one genus Didelphys ; * of these species one is 

 common in the United States of North America, 

 four or five inhabit Mexico, and the remainder are 

 found in South America,t where they are known to 

 extend as far south, on the eastern side of the con- 

 tinent, as Maldonado, and one species was discovered 

 by Mr. Darwin on the opposite side of the Cordilleras, 

 at Valparaiso. 



In the Indian Archipelago, the Marsupial animals 



* Cheirontctes, which is proposed as a generic name for an 

 Opossum which inhabits certain rivers in S. America, can only 

 be regarded in the light of a sub-genus or slightly aberrant 

 form of Didelphys. 



f Mr. Bennet describes two species, in the Proceedings 

 of the Zoological Society, from California, bo.th of which 

 are closely allied to the common Opossum of the United 

 States. 



