The muddy ground under the mangrove-trees is covered with soldier-crabs, which quickly slink into their holes on any symptom of danger. When the ebbing tide retires, myriads of minute crabs emerge from their underground quarters, and begin to work like so many busy bees. Soon many miles of the smooth sand become rough with the results of their labour. They are toiling for their daily bread: a round bit of moist sand appears at the little labourer's mouth, and is quickly brushed off by one of the claws; a second bit follows the first; and another, and still another come as fast as they can be laid aside. As these pellets accumulate, the crab moves sideways, and the work continues. The first impression one receives is, that the little creature has swallowed a great deal of sand, and is getting rid of it as speedily as possible: a habit he indulges in of darting into his hole at intervals, as if for fresh supplies, tends to strengthen this idea; but the size of the heaps formed in a few seconds shows that this cannot be the case, and leads to the impression that, although not readily seen, at the distance at which he chooses to keep the observer, yet that possibly he raises the sand to his mouth, where whatever animalcule it may contain is sifted out of it, and the remainder rejected in the manner described. At times the larger species of crabs perform a sort of concert; and from each subterranean abode strange sounds arise, as if, in imitation of the songsters of the groves, for very joy they sang! We found some natives pounding the woody stems of a poisonous climbing- plant (_Dirca palustris_) called Busungu, or poison, which grows abundantly in the swamps. When a good quantity was bruised, it was tied up in bundles. The stream above and below was obstructed with bushes, and with a sort of rinsing motion the poison was diffused through the water. Many fish were soon affected, swain in shore, and died, others were only stupefied. The plant has pink, pea-shaped blossoms, and smooth, pointed, glossy leaves, and the brown bark is covered with minute white points. The knowledge of it might prove of use to a shipwrecked party by enabling them to catch the fish. The poison is said to be deleterious to man if the water is drunk; but not when the fish is cooked. The Busungu is repulsive to some insects, and is smeared round the shoots of the palm-trees to prevent the ants from getting into the palm wine while it is dropping from the tops of the palm-trees into the little pots suspended to collect it.