The marsh tortoises, or _Emydæ_, have their chief seat in tropical America and the Indian Archipelago, where an abundance of swamps, lagoons, lakes, pools, and gently-flowing rivers favours the increase of their numbers. In the month of September, as soon as the sand-banks begin to be uncovered, the females deposit their eggs, scraping hollows of a considerable depth, covering them over carefully, smoothing and beating down the sand, and then walking across and across the place in various directions, for the purpose of concealment. There are such numbers of them, that some beaches are almost one mass of eggs beneath the surface, and here the Indians come to make oil. A canoe is filled with the eggs, which are all broken and mashed up together. The oil rises to the top, and is skimmed off and boiled, when it will keep, and is used both for light and for cooking. During this operation, the neighbouring strand swarms with carrion vultures, and the smell of the offal attracts also a number of alligators, eager to come in for their share of the feast. Millions of eggs are thus annually destroyed, and of those that remain a very small portion only arrives at maturity. When the young tortoises issue from the egg and run to the water, many enemies are awaiting them. Great alligators open their jaws, and swallow them by hundreds; the jaguars and the smaller felidæ from the forest come to 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 marsh-tortoises may be said to form the connecting link between the eminently aquatic marine and river chelonians and the land-tortoises, as the formation of their feet, armed with sharp claws or crooked nails, and furnished with a kind of flexible web, connecting their distinct and movable toes, allows them both to advance much quicker on the dry land than the latter, and to swim rapidly either on the surface or in the depth of the waters. Endowed with more rapid powers of locomotion, they are not vegetarians, like the land-tortoises, but chiefly live on mollusks, fishes, frogs, toads, and annelides.