As is so sadly true of most marine organisms, we know far too little of their habits. What is the reason for the strange leaps they make into the air, falling back on to the water with a thudding splash that can be heard a mile away? It is usually done by night, a circumstance that adds to the strangeness of this sudden obtrusion upon our minds of the existence of a scarcely known world beneath the water, which we, in our preoccupation with our own half of the world, had almost forgotten. So much for the prey, now to its hunting. They occasionally appear on the surface, two or three pairs swimming together, the black point of the side fin appearing above water, now on this side, now on that. On one occasion I was out in a small sailing boat with three or four canoes of pearl-divers, and as the fish when chased went down wind, we were able to follow, spread out in a long line so that whichever vessel saw the prey could signal to the others. We thus kept the chase going for an hour or more, striking with fish spears repeatedly, but as these are not barbed, and as in all that hundred or more square feet of body the brain and heart occupy but a few square inches, the spears may go through and through, and be withdrawn again when all the line has been run out, with no appreciable damage to the animal. So on this occasion we made no capture, but the hour’s chase over this silver sea with glimpses of mystery beneath was a pleasure to remember. Another chase, also without capture, was stranger still. I found a pearling canoe moving over the dead calm sea with no visible means of propulsion. On reaching them I found they had made fast to a fish and dared not play the line attached to the spear for fear of its breaking away. Looking down into the blue with a water glass one saw the dim shadow of one of those monsters, _Pristis_ by name, half shark, half ray, in which the snout is prolonged into a beak, into the sides of which are set formidable teeth, an object frequently exposed for sale in curio shops as the sawfish’s jaw. This was one of the largest species of the genus and must have been ten to twelve feet long without the toothed snout.