324 ZOOLOGY OF
alligators open their jaws and swallow them by hundreds ; the jaguars from the forest come and feed upon them; eagles and buzzards, and the great wood ibises attend the feast ; and when they have escaped all these, there are many ravenous fishes which seize them in the stream.
The Indians catch the full-grown turtles, either with the hook, net, or arrow. The last is the most ingenious method, and requires the most skill. The turtle never shows its back above water, only rising to breathe, which it does by protruding its nostrils almost imperceptibly above the surface ; the Indian's keen eyes perceive this, even at a considerable distance ; but an arrow shot obliquely would glance off the smooth flat shell, so he shoots up into the air with such accurate judgment, that the arrow falls nearly vertically upon the shell, which it pene- trates, and remains securely fixed in the turtle's back. The head of the arrow fits loosely on to the shaft, and is connected with it by a long fine cord, carefully wound round it ; as the turtle dives, they separate, the light shaft forming a float or buoy, which the Indian secures, and by the attached cord draws the prize up into his canoe. In this manner almost all the turtles sold in the cities have been procured, and the little square vertical hole of the arrow-head may generally be seen in the shell.
Besides the great tataruga (Podocnemis expansd), there are several smaller kinds, also much used for food. The Tracaxa {Emys tracaxa, Spix) and the Cabecudo {E. macrocephala, Spix) have been described by the French naturalists, Dumeril and Bibron, as one species, under the name of Peltocephalus tracaxa ; but they are quite distinct, and though their characters are perhaps not easy to define, they could never be confounded by any one who had examined them in the living state. They are found too in different localities. The tracaxa is abundant in the Amazon, in the Orinooko, and in the Guaviare, all white- water rivers, and very scarce in the Rio Negro. The cabecudo is very abundant in the Rio Negro and in the Atabapo, but is not found in the Guaviare or the Amazon, appearing to be confined to the black-water streams. I obtained ten distinct kinds of river tortoises, or Chelydidcs, and there are also two or three kinds of land-tortoises inhabiting the adjacent district.
As might be expected in the greatest river in the world, there is a corresponding abundance and variety of fish. They
