On the Gapo, or submerged lands, however, a considerable difference in the vegetation appears. The palms are here often more numerous than in other parts. This is the region where the cacao-tree and prickly sarsaparilla grow. Here the underwood is less dense, the sipos retiring to weave their tracery among the upper branches alone. Though during the dry season the vegetation springs up with wonderful rapidity, it is swept away by the next overflow. Here the lovely orchis tribe adorn the gloomy shades with their brilliant flowers. Among the most beautiful is the oncidium, of a yellow hue, often seen--apparently suspended in air between the stems of two trees--shining in the gloom, as if its petals were of gold. In reality it grows at the end of a wire-like stalk a yard and a half long, springing from a cluster of thick leaves on the bark of a tree; others have white and spotted blossoms, growing sometimes on rotten logs floating on the water, or on moss and decayed bark just above it. Still more magnificent is the Flor de Santa Ana, of a brilliant purple colour, emitting a most delicious odour. Peculiar and strange is this region of the Gapo. When the waters are at their height it can be traversed in all directions. The trees which grow on it, and the animals which here have their abodes, appear to differ from those of other districts. Let us accompany the naturalist Wallace, in his canoe, through a district of this description; now forcing our way under branches and among dense bushes, till we get into a part where the trees are loftier and a deep gloom prevails. Here the lowest branches of the trees are level with the surface of the water, many of them putting forth flowers. As we proceed we sometimes come to a grove of small palms, the leaves being now only a few feet above us. Among them is the maraja, bearing bunches of agreeable fruit, which, as we pass, the Indians cut off with their long knives. Sometimes the rustling of leaves overhead tells us that monkeys are near, and we soon see them peeping down from among the thick foliage, and then bounding rapidly away. Presently we come out into the sunshine, on a lake filled with lilies and beautiful water-plants, little bladder-worts, and the bright blue flowers and curious leaves with swollen stalks of the pontederias. Again we are in the gloom of the forest, among the lofty cylindrical trunks rising like columns out of the deep water; and now there is a splash of fruit falling around us, announcing that birds are feeding overhead, and we discover a flock of parrakeets, or bright blue chatterers, or the lovely pompadour, with its delicate white wings and claret-coloured plumage. Now, with a whir, a trogon on the wing seizes the fruit, or some clumsy toucan makes the branches shake as he alights above our heads.