"As a matter of fact, they do not fly at all; but the membrane which unites their limbs acts like a parachute in keeping them up in the air, and materially assists them in some of their prodigious leaps." "Can they run as fast as squirrels?" "Nothing like it; they do not, indeed, often come down to the ground; but their activity on trees renders them not unworthy of their family." "I thought," observed Lucien, "that bats were the only mammals that could fly." "There is also the flying _phalanger_," observed my friend; "an animal of the marsupial order, which is a native of Australia, and somewhat resembles the opossum. It is said that, when it catches sight of a man, it hangs itself up by the tail, and does not dare to move; but I think this story will do to go along with l'Encuerado's about the glass-spider." The Indian started off straight to the bivouac, and I led my companions by the side of the stream, admiring as we passed some magnificent trees. One of these was covered with brown fruit, with whitish insides, which had a rather nice acidulated taste. I hastened to pick half a dozen of them, knowing what a treat they would be to my servant. As we went on, the banks of the stream gradually became lower, and ere long a lake, deliciously shaded by cypresses, poplars, oaks, and ebony-trees, opened to our view. I sat down upon a rock, with Sumichrast and Lucien by my side, and from whence my eye could wander all over the blue and transparent water. We kept silent, being charmed with the smiling grandeur of this retired corner of the world. Birds came flying by, and, settling down close to us, warbled for an instant--then again took flight, after having given us time to admire the rich colors of their plumage. The motionless water was covered by long-legged insects with transparent wings, which seemed to skim over the polished surface as if impelled by some invisible agency. Sometimes an azure and purple attired dragon-fly flitted by, and all the insects fled at its approach, like sparrows before a hawk. A brilliantly-colored butterfly dashed against the voracious insect, and a furious combat took place between them; but the dragon-fly, which was eventually the conqueror, was in turn vanquished by a bird. We were just moving off, when the deep water seemed to be agitated, and, although on the surface the flies and gnats continued their evolutions, the fish in hasty flight disappeared, and communicated their terror even to the water-snakes. A tortoise, however, seemed to deem it unnecessary to retreat, only drawing its head and feet under its shell. Almost immediately an animal swam vigorously up to the reptile, and, having stopped to smell at it, continued its course. [Illustration: "The sun was just setting."] "Are there such things as opossum-fishes?" asked Lucien, surprised. "It is an otter," said I, in a low voice.