Infinitely more dangerous than this fabulous serpent, more dreadful even than the cayman or the anaconda, are the pirangas, a small species of salmon, which in many places attack the unfortunate swimmer with their sharp teeth, and taint the waters with his blood. Castelnau saw how a stag, which threw itself in the river to avoid the hunter’s pursuit, was soon killed by the pirangas. The Roman knight that cast his slaves to the murænas,[8] would, no doubt, have been rejoiced to people his ponds with fish like these; and Tiberius would have been delighted to have possessed them at Capræa! A night encampment in the Amazons is, however, not always so pleasant as the foregoing description might lead one to suppose; for many islands are so infested with mosquitos that they are quite intolerable, and the growl of a jaguar or the sight of a crocodile (for this animal is by no means afraid of fire) not unfrequently disturbs the company. Complete security from these persecutions and visits is only to be found in the centre of the stream; for here a cayman is seldom seen, and the wings of the insects are too weak to carry them to such a distance from the shore. The most striking features of the Amazons, besides its vast expanse of smooth water, generally from three to six miles wide, are the great beds of aquatic grass which line its shores, large masses of which are often detached and form floating islands; the quantity of fruits and leaves and great trunks of trees which it carries down, and its level banks clad with high unbroken masses of verdure. In places the white stems and leaves of the Cecropias give a peculiar aspect, and in others the straight dark trunks of lofty forest trees form a living wall along the water’s edge. There is much animation, too, on this great stream. Numerous flocks of parrots and the great red and yellow macaws fly across every morning and evening, uttering their hoarse cries. Many kinds of herons and rails frequent the marshes on its banks, and a great handsome duck (_Chenalobex jubata_) is often seen swimming about the bays and inlets. But perhaps the most characteristic birds of the Amazons are the gulls and terns which are in great abundance. All night long their cries are heard over the sand banks where they deposit their eggs, and during the day they may constantly be seen, sitting in a row on a floating log, sometimes a dozen or twenty side by side, and going for miles down the stream as grave and motionless as if they were on some very important business. These birds deposit their eggs in little hollows in the sand, and the Indians say that during the heat of the day they carry water in their beaks to moisten them, and prevent them being roasted by the scorching sun. Besides these there are divers and darters in abundance, porpoises are constantly blowing in every direction, and alligators are often seen slowly swimming across the river. An amazing number of fishes peoples the waters of the Amazons