1 8 The Naturalist in La Plata. 



Didelphys crassicaudata has a long slender, wedge- 

 shaped head and body, admirably adapted for push- 

 ing through the thick grass and rushes ; for it is 

 both terrestrial and aquatic, therefore well suited 

 to inhabit low, level plains liable to be flooded. On 

 dry land its habits are similar to those of a weasel ; 

 in lagoons, where it dives and swims with great 

 ease, it constructs a globular nest suspended from 

 the rushes. The fur is soft, of a rich yellow, reddish 

 above, and on the sides and under surfaces varying 

 in some parts to orange, in others exhibiting beau- 

 tiful copper and terra-cotta tints. These lovely 

 tints and the metallic lustre soon fade from the fur, 

 otherwise this animal would be much sought after 

 in the interests of those who love to decorate them- 

 selves with the spoils of beautiful dead animals 

 beast and bird. The other opossum is the black 

 and white Didelphys azarae ; arid it is indeed 

 strange to find this animal on the pampas, although 

 its presence there is not so mysterious as that of 

 the tuco-tuco. It shuffles along slowly and awk- 

 wardly on the ground, but is a great traveller 

 nevertheless. Tschudi met it mountaineering on 

 the Andes at an enormous altitude, and, true to its 

 lawless nature, it confronted me in Patagonia, where 

 the books say no marsupial dwells. In every way 

 it is adapted to an arboreal life, yet it is everywhere 

 found on the level country, far removed from the 

 conditions which one would imagine to be necessary 

 to its existence. For how many thousands of years 

 has this marsupial been a dweller on the plain, all 

 its best faculties unexercised, its beautiful grasping 

 hands pressed to the ground, and its prehensile tail 



