Strolling one day in what is euphemistically termed, in equatorial latitudes, 'the cool of the evening,' along a tangled tropical American field-path, through a low region of lagoons and watercourses, my attention happened to be momentarily attracted from the monotonous pursuit of the nimble mosquito by a small animal scuttling along irregularly before me, as if in a great hurry to get out of my way before I could turn him into an excellent specimen. At first sight I took the little hopper, in the grey dusk, for one of the common, small green lizards, and wasn't much disposed to pay it any distinguished share either of personal or scientific attention. But as I walked on a little further through the dense underbrush, more and more of these shuffling and scurrying little creatures kept crossing the path, hastily, all in one direction, and all, as it were, in a formed body or marching phalanx. Looking closer, to my great surprise, I found they were actually fish out of water, going on a walking tour, for change of air, to a new residence--genuine fish, a couple of inches long each, not eel-shaped or serpentine in outline, but closely resembling a red mullet in miniature, though much more beautifully and delicately coloured, and with fins and tails of the most orthodox spiny and prickly description. They were travelling across country in a bee-line, thousands of them together, not at all like the helpless fish out of water of popular imagination, but as unconcernedly and naturally as if they had been accustomed to the overland route for their whole lifetimes, and were walking now on the king's highway without let or hindrance.