A NATURALIST IN BRAZIL 



its sharp teeth this terrible fish, which attains the length of the 

 forearm, tears whole pieces out of the flesh of swimming animals, 

 and since the Piranhas appear in shoals directly they scent blood, 

 the victim is soon stripped to the bones. The Piranhas and not the 

 crocodiles are the real danger in the Brazilian rivers. But the 

 Candiru, a little thread-like Silure, is an equally unpleasant acquain- 

 tance. This creature forces its way into the urethra of bathers, and 

 owing to the spines on the gill-covers it cannot be extracted. 



The Electric Eel or Poraque is another Brazilian fish; on either 

 side of the spine this fish has developed electric batteries, a shock 



from which will stun a horse. And 

 in the Arapaima of the Amazon 

 the world of fresh-water fish has its 

 largest representative. 



The number of insects in Brazil 

 is almost infinite. Nowhere else are 

 there so many species of butterflies ; 

 and the vivid blue loveliness of the 



. , , Morphidae is not excelled by any 



Fig. 1 1 . — Piranha, one-sixth natural , , _ , » 



g-^e other butterfly on earth. Among 



the Coleoptera we find those 



amazing giants of the beetle world, the Hercules Beetle and the 



Elephant Beetle. Even the bugs have evolved magnificent forms in 



Brazil. 



South America thus received the basic forms of her fauna from 

 the northern mainland, by way of a bridge of land, and was enabled 

 to retain them and transform them in a manner both prolific and 

 peculiar, for this bridge sank beneath the sea about the middle of 

 the Tertiary period. In proud isolation the continent breasted the 

 ocean, and for long geological periods was protected from further 

 invasion, so that the much older forms of the northern continent 

 fell victims to younger competitors. When, about the middle of the 

 Tertiary period, a wide isthmus came into being, and towards the 

 end of the period the narrow bridge which we now call the Isthmus 

 of Panama, the fauna of South America had already become so far 

 established that the new migrations were unable to exterminate it. 

 Such migrations now occurred in both directions. From South 

 America humming-birds, parrots, monkeys, butterflies and other 

 insects wandered northwards, finding suitable conditions of life in 

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