"We left Ega, on our first trip to visit the sentinels while the turtles were yet laying, on the 26th of September. We found the two sentinels lodged in a corner of the praia, or sand-bank, where it commences, at the foot of the towering forest-wall of the island; having built for themselves a little rancho with poles and palm-leaves. Great preparations are obliged to be taken to avoid disturbing the sensitive turtles, who, 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 warn off any fisherman who wishes to pass near the place. Their fires are made in a deep hollow near the borders of the forest, so that the smoke may not be visible. The passage of a boat through the shallow waters where the animals are congregated, or the sight of a man, or a fire on the sand-bank, would prevent the turtles from leaving the water that night to lay their eggs; and, if the causes of alarm were repeated once or twice, they would forsake the praia for some quieter place. Soon after we arrived, our men were sent with the net to catch a supply of fish for supper. In half an hour, four or five large basketsful were brought in. The sun set soon after our meal was cooked: we were then obliged to extinguish the fire, and remove our supper-materials to the sleeping-ground, a spit of land about a mile off; this course being necessary on account of the musquitoes, which swarm at night on the borders of the forest. "I rose from my hammock at daylight, and found Cardozo and the men already up, watching the turtles. The sentinels had erected for this purpose a stage about fifty feet high, on a tall tree near their station, the ascent to which was by a roughly-made ladder of woody lianas. The turtles lay their eggs by night, leaving the water in vast crowds, and crawling to the central and highest part of the praia. These places are, of course, the last to go under water, when, in unusually wet seasons, the river rises before the eggs are hatched by the heat of the sand. One would almost believe from this that the animals used forethought in choosing a place; but it is simply one of those many instances in animals where unconscious habit has the same result as conscious prevision. The hours between midnight and dawn are the busiest. The turtles excavate, with their broad-webbed paws, deep holes in the fine sand; the first-comer, in each case, making a pit about three feet deep, laying, its eggs (about a hundred and twenty in number), and covering them with sand; the next making its deposit at the top of that of its predecessor; and so on, until every pit is full. The whole body of turtles frequenting a praia does not finish laying in less than fourteen or fifteen days, even when there is no interruption. When all have done, the area over which they have excavated is distinguishable from the rest of the praia only by signs of the sand having been a little disturbed.