Fig. 39.—Trionyx Ægyptiacus.
M. Lesueur states that towards the beginning of May the females of Gymnopus spinifera, belonging to this division, seek out sunny sandy spots on the river's bank for the deposit of their eggs; they are not deterred from choosing steeps of ten or fifteen feet for this purpose. Their eggs are spherical, and more fragile than those of the Marsh Tortoise. They deposit from fifty to sixty at a time. None of this group are found in Europe. The fresh-water lakes and rivers of the warmer regions, such as the Nile and the Niger, in Africa, the Mississippi, the Ohio, and the Amazon rivers, in America, the Euphrates and the Ganges, in Asia, are its habitats. Among other remarkable species in the group we here represent Trionyx Ægyptiacus, [Fig. 39], supposed to be the Εμυς of Aristotle.
No modern naturalist has done more to illustrate the habits of the Fresh-water Turtle than Mr. Bates, in his highly interesting work, "The Naturalist on the Amazon." "The great Fresh-water Turtle (probably Platemys æfipes) of the Amazon or Solimoens grows on the upper river," he says, "to an immense size, a full-grown one measuring nearly three feet in length, by two in breadth, and is a load for the strongest Indian. Every house (in Ega) has a little pond called a corral, or pen in the back-yard, to hold a stock of these animals through the season of dearth—the wet months. Those who have a number of Indians in their employ send them out for weeks, when the waters are low, to collect a stock, and those who have not purchase their supply—this is attended with some difficulty however, as they are rarely offered for sale. The price of Turtles, like that of other articles of food, has risen greatly since the introduction of steam-vessels. Thus, when I arrived, in 1850, a middle-sized one could be bought for ninepence, but when I left, in 1859, they were with difficulty obtained for eight or nine shillings each. The abundance of Turtles varies with the amount of diurnal subsidence of the waters. When the river sinks less than the average, they are scarce; but when high waters have prevailed, they can be caught in abundance, their haunts being less restricted, and appropriate breeding-places more numerous.
"The flesh is very tender, palatable, and wholesome; but it is very cloying, and every one ends sooner or later by becoming thoroughly surfeited. I became so sick of Turtle in the course of two years that I could not bear the smell of it, although nothing else was to be had; consequently I suffered from actual hunger."
One of the most amusing sketches in Mr. Bates' book is a journey he made on the Solimoens, during which he visited the praias, or sand-islands, the Turtle-pools in the forests, and the by-streams and lakes of the great river. His companion was Cardozo, who was a sort of official superintendent of the diggers for Turtles' eggs on the sand-banks of Shimuni, the island lying nearest to Ega. There are four or five of these Royal Praias, as they are called, in the district, each having its commandant, whose business is to see that every inhabitant has an equal chance in the egg-field.
"The pregnant Turtles descend from the interior pools of the main river in July and August, before the outlets dry up, and seek their favourite sand-island in countless swarms; for it is only a few praias that are selected by them out of the great number existing. When hatched, the young animals remain in the pools throughout the dry season; for these breeding-places of the Turtle then lie from twenty to thirty feet above the level of the river, and are accessible only by cutting a path through the dense forest." On the 26th of September Mr. Bates left Ega with his companion, who was about to visit the sentinels placed to mark when and where the Turtles laid their eggs. Their conveyance was a stoutly-built canoe, or igareté, arranged for two paddlers, with an arched covering in the stern, under which three persons could sleep pretty comfortably. The swift current of the Solimoens carried them rapidly to the large wooded island of Baria, which divides the river into two broad channels. Shimuni lies in the middle of the north-easterly passage. They were quickly paddled across, reaching it an hour before sunset. The island is about three miles long and half a mile broad. The forest which covers it rises to an immense uniform height, presenting all round a compact and impervious front, the uniformity being interrupted here and there by a singular tree, called Mulatto wood, whose polished dark-green trunk is seen conspicuously through the mass of vegetation. The sand-bank lies at the upper end of the island, and extends several miles, presenting an irregular surface of ridges and hollows. At the further shore to the north-east, where no forest line shuts out the view, the white, rolling, sandy plain stretches away to the horizon; to the south-west a channel, about a mile in breadth, separates Baria from Shimuni.
Arrived at this island, Mr. Bates proceeds to describe with great minuteness the operations of the Turtles, as well as those of the sentinels placed to watch them.
"We found two sentinels," he says, "lodged in a corner of the praia, where it commences at the foot of the towering forest west of the island, having built themselves a little rancho with poles and palm-leaves. Great precautions are obliged to be taken to avoid disturbing the vigilant Turtles, which, previous to crawling ashore to lay, assemble in great shoals off the sand-bank. The men during this time take care not to show themselves, and they warn off any fisherman who attempts to pass near the place; for the passage of a boat, or the sight of a man, or a fire on the sand-bank, would prevent their laying their eggs that night, and if repeated, they would forsake the praia for some quieter place."
After a night spent under a temporary shed rapidly constructed for himself and companion, Mr. Bates rose from his hammock shivering with cold.
"Cardoza and the men were already watching the Turtles on a stage erected on a tall tree fifty feet high; from this watch-tower they are enabled to ascertain the place and date of successive deposits of eggs, and thus guide the commandant in fixing the time for his general invitation to the Ega people. The Turtles lay their eggs during the night, leaving the water in vast crowds when all around is quiet, when they crawl to the central and highest part of the praia. The hours between midnight and dawn are those when the Turtles excavate, with their broad, webbed paws, deep holes in the fine sand, the animal in each case making a pit about three feet deep; in this pit it lays its eggs, about a hundred and twenty in number, covering them over with sand; then a second deposit is placed on the top of the first, and so on until the pit is full." This goes on for about fourteen days. "When all have done, the area, or taboliero, over which they have been digging is only distinguished from the rest of the praia by signs of the sand having been a little disturbed.