The mangroves have still another method of gaining new territory. Aërial roots are thrown out from branches high in air, swinging downward and outward with a curve which sometimes wins three or four yards ahead. Like hawsers thrown from a vessel to a wharf these roots clutch at the mud beneath, but where the current runs swiftly they swing and dangle in vain, until they have grown so heavy that they touch bottom some distance downstream. We made use of these dangling roots as anchors for our canoe, bending the elastic unattached end upward and springing it over the gunwale. Throughout all this great region there is not a foot of solid ground. In one place we pushed a tall shoot some eight feet in height straight down through the mud, and it went out of sight. A man falling on this mud, out of reach of aid, would vanish as in a quick-sand. So the wild creatures of the mangroves must either swim, fly, or climb. No terrestrial beings can exist there. We once selected a favorable place, and for fifty yards made our way over the roots and branches before exhaustion and an impassable gap of mud and water stopped all progress. As never before we realized how safe from man are the denizens of these strange swamps. Monkeys fled swiftly before us, birds rose and flew overhead, while we painfully crept and pulled ourselves along over the slippery stems. [Illustration: FIG. 4. YOUNG MANGROVE PLANTS.] More wonderful even than the coral polyps are these mangroves, for by this plant alone all this region has been rescued from the sea and built up into land. In future years, as the mud banks become higher and are fertilized by the ever-falling leaves, other growths will appear, and finally the coast of the continent will be thus extended by many scores of miles of fertile soil. A network of narrow channels stretches through this wilderness and allowed us to explore the far interior in our shallow curiara or dug-out. Thus we spent days and weeks in search of the creatures which lived in this land of a single tree, and here we learned how delightful the climate of such a region can be. Every night we slept under blankets, and during the day the temperature ranged from 66° at five and six o’clock in the morning to about 86° at noon, although we were within nine degrees of the equator.[B] One could paddle all day with more comfort than on a hot summer day in the north. By day mosquitoes were generally absent, and only a few biting flies reminded us of the “terrible insect scourges” of the tropics. Life was delightfully new and strange, with the spice of danger ever attendant upon the exploration of unknown lands. [Illustration: FIG. 5. THE CRUCIFIX IN THE CATFISH.]