THE VIRGINIAN OPOSSUM. 
DiDELPHlS ViRGlNIANA. Cuv. 
The further we advance in our knowledge of Marsupial 
animals, the more firmly do we become convinced of 
the impropriety of their separation as a distinct and 
isolated group. When we see that the single pecu- 
liarity that unites them is bestowed upon types of form 
so widely different from each other, we cannot consider 
this simple metastasis of function in a certain set of 
organs alone, however great the importance of that 
function in the animal economy, as furnishing sufficient 
ground for the overthrow of every principle of classifi- 
cation, and for setting at nought some of the most 
strongly marked affinities that the animal kingdom 
affords. How striking, for instance, is the passage 
from the Insectivorous Carnivora, through the Opos- 
sums and Dasyuri, to the Civets and other more purely 
