102 The Naturalist in La Plata. 
than any animal I had ever observed. I have seen 
an old female opossum (Didelphys azaree) with 
eleven young, large as old rats—the mother being 
less than a cat in size—all clinging to various 
parts of her body; yet able to climb swiftly and 
with the greatest agility in the higher branches of 
a tree. The actual weight was in this case rela- 
Didelphys azarze and young. 
tively much greater than in that of the female bat ; 
but then the opossum never quitted its hold on 
the tree, and it also supplemented its hand-lke 
feet, furnished with crooked claws, with its teeth 
and long prehensile tail. The poor bat had to 
seek its living in the empty air, pursuing its prey 
with the swiftness of a swallow, and it seemed 
