156 THE TOWER MENAGERIE. 
bag, in which the young are contained from a very early 
period, in which the process of suckling takes place, and 
in which, even for some time after they have acquired 
sufficient size and strength to leave it, the little ones 
continue to take refuge. 
But the presence of this one anomalous characteristic 
is accompanied by so many striking discrepancies in 
other parts, that, limited as this tribe is in number, most 
of the principal forms of Mammalia find analogous 
representations among its groups. Thus the Opossums 
exhibit characters in some measure intermediate between 
the Quadrumana and the Carnivora, to which latter the 
Dasyuri, another Marsupial group, closely resembling 
the Civets in form and habits, approach very nearly ; 
while the herbivorous races of the tribe might occupy a 
station between the Rodent and Ruminant Orders, with 
each of which they exhibit various degrees of relation- 
ship. This want of uniformity in the essential parts of 
their organization necessarily gives rise to much diffi- 
culty in determining their position in the system. The 
mode of classification now most generally followed is 
perhaps, under all the circumstances, the best that could 
at the present moment be adopted; although it must be 
owned that the purely herbivorous species arrange them- 
selves with a very ill grace under a subdivision of the 
order Carnivora. Placed, however, as they are at the 
end of that order, and immediately before the Rodentia, 
the regular gradations from the type of the former to 
that of the latter, which occur in their different groups, 
become most distinctly manifest. 
With the exception of the Opossums, which are natives 
of America, the tribe is peculiar to New Holland and its 
