FAUNA OF AMAZONIA. 107 



type. But on the other hand there are 38 members of the monkey family, 

 all climbers and all with prehensile tails. The cercoleptes, a species of bear, is also 

 of exclusively arboreal habits, and of the four kinds of ant-eaters {myrmecophaga) 

 studied by Bates, three live in the trees, as do also the degenerate descendants of 

 the colossal megatherium (sloth), besides various squirrels, snakes, and other 

 reptiles. 



Gulls and the frigate-bird ascend the Amazons to the Peruvian plains 2,500 

 miles from the sea, while the manatee and dolphins frequent all the large affluents 

 as far as the first rapids. But the various species of cetaceans have acquired 

 exclusively fluvial forms. The water boa [eunectes murinus), which sometimes 

 attacks man, acquires enormous proportions in the Napo basin, where Osculati saw 

 one which appeared to him some 50 or 60 feet long. 



The Amazons waters are infested by the formidable jncare uassu, or great 

 crocodile ; but the turtle, which formerly swarmed in the main stream, has been 

 nearly exterminated or driven up the affluents by the reckless destruction of its 

 eggs. Both of these animals withdraw to the lakes and tributaries during the 

 rainy season, returning in the dry period, or else burying themselves in the mud 

 during the summer months. Saurians and fishes of identical species vary in colour 

 according to the darker or lighter tints of the fluvial waters frequented by them. 



All the running waters teem with fishes, and the 600 or 700 species estimated 

 by Spix were raised by Agassiz to nearly 2,000 for the Amazons alone, that is, 

 twice as many as in the Mediterranean, and more than in the whole Atlantic. The 

 Hyanuary lagoon west of the Bio INegro confluence contains over 200, or more 

 than all the rivers and lakes of Eurojse together. Some are extremely ferocious ; 

 i\\e piranhas (fetragoiioptenis), despite their small size, attack man with great fury, 

 and often snap off the lips of dogs and horses drinking in the streams infested by 

 them. 



Although poor in some bird forms, notably humming birds, Amazonia abounds 

 in others, and Wallace alone collected over 500 different kinds. Aquatic beetles 

 are rare, but on the other hand no less than 700 species of butterflies occur within 

 a radius of four miles round Para. It was the extreme variety of the lepidoptera 

 that enabled Bates to prosecute those comparative studies on transformation and 

 mimicry that supplied so many arguments in support of Darwin's theory on the 

 Origin of Sjjecies. Some of the winged pests, such as the nocturnal mosquito a.nd 

 the piuni or day fly, render certain riverside districts in the Purus valley quite 

 uninhabitable ; the sauba ant also [œcodoma cephalotes), which lines its underground 

 galleries with leaves, makes all tillage impossible m many places. Coffee planta- 

 tions laid out at great cost have been utterly destroyed by its invading hosts. The 

 galleries, which extend to a distance of 160 and even 200 feet, are the work of a 

 delving population provided with a frontal eye like the fabulous cyclops or the 

 modern miners with their Davy lamps. A denizen of these subterranean abodes 

 is the amphisbœna, " mother of the saubas," a harmless snake said by the natives 

 to have two heads. Even more dreaded than the sauba is the fonniga do fogo, or 

 " fire-ant " {ïmjrmica rubra), which has at times put whole communities to flight. 



