THE ANIMAL WORLD OF BRAZIL 



coast fits into the Gulf of Guinea, and slowly receded across the 

 Atlantic Ocean. A Sao Paulo zoologist, the late H. von Ihering, 

 even sketched a southern continent on the map of the early Tertiary 

 period, and a second continent connecting South America with 

 Africa. The theory that South America received many of its animal 

 species from the northern focus of creation, by way of Africa, has, 

 as a matter of fact, much in its favour. The primitive forms of 

 the Caviidae of South America occurred, in their oldest forms, in the 

 early deposits of Europe ; Africa yields a few relics of them, but 

 North America none. Nearly related forms are found in the fresh- 

 water fish of both hemispheres, which is a particularly striking proof 

 of a former connection, since these creatures would never swim 

 across the sea, nor could they be carried across it by drifting wood. 

 Among the fishes are the incubating Siluridae, of which I shall speak 

 in Chapter XIV; beyond a few Indian species, these occur only in 

 Africa and South America, and the same may be said of various 

 snakes. 



Let us now consider the mammals of Brazil individually, and see 

 what they tell us of old continental junctions. 



Let us take, as one of the lowest forms of warm-blooded animals, 

 the Marsupials (Plate 27). These animals derive their name from a 

 pouch on the abdomen, in which the mother lays her oflfspring — 

 helpless and undeveloped as a creature prematurely born — where 

 it fastens so firmly on the milk-glands which empty themselves into 

 the pouch that a kind of growth connects its mouth to the nipple, 

 while the windpipe of the little creature is pushed forward almost 

 into the nose, so that the stream of milk shall not incommode its 

 breathing. 



As primitive mammals the marsupials have been driven south- 

 wards by the continual emergence of new forms. They are found 

 to-day in Australia and the neighbouring islands, where, being early 

 shut oflf by the sea, they were able to call a halt and divide into 

 many species, of which the best known are the Kangaroos. In South 

 America too the marsupials have continued to evolve, though not 

 so prolifically as in Australia; apparently because the western 

 continent remained joined to the northern mainland after their 

 migration, so that new competitors for space and nourishment 

 appeared. 



The South American marsupials are carnivora, which eat small 

 mammals, birds, and insects. Only one form, the Water-Opossum, 



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