Bringing the _Seal_ round in a perilously close circle, he steered her straight and true for her monstrous enemy’s side. This offensive movement seemed to puzzle the saurian, and he attempted to avoid the swooping vessel. But she was too quick for him. With a shock that almost jerked Garth from his feet, the vessel’s sharp prow struck the reptile’s heaving side, about midway between the two starboard paddles. A crimson torrent spurted from the wound, deluging the _Seal’s_ bright plates, and turning her spotless deck into a veritable shambles. On the instant Wilson flung over his levers, and, under reversed engines, the submarine leapt back from her stricken foe. Yet, quick as she moved, the great tail of the ichthyosaurus moved quicker. With a stroke like that of a steam hammer, it struck the _Seal’s_ hull just below water, starting a couple of plates, through the interstices of which the water commenced to pour in an ever-increasing stream. Though sorely stricken the great fish-lizard was not yet defeated. Swinging round, he churned after the retreating vessel, his roar changed to a shrill screaming. Again the inventor signalled for full speed ahead, and, for the second time, the vessel plunged down upon her relentless pursuer. With marvellous swiftness the huge brute swerved from his course, but Garth, with a turn of the wheel, followed his movement. The inventor was determined that he would finish this reptile once and for all. The bleeding side of the creature offered an excellent mark, and straight for this Garth drove the vessel. Like a rocket she shot forward, and the saurian’s ribs snapped like matchwood as once more she struck the towering carcase. There came a terrible death-cry from the huge reptile; then, as the _Seal_ drew slowly away, the brute leapt clear out of the water, and fell with a thunderous crash across the submarine’s deck. A savage exclamation burst from Garth as the _Seal_ commenced to sink beneath the enormous weight of the monster’s body. The brute’s paddles were thrashing madly in its death flurry, and the booming strokes of the giant tail seemed to make the whole underworld ring. Alarmed by the uproar, the engineer came rushing up into the turret. “What’s happened?” he cried; then his eye took in the peril of the situation. The water was fast closing over the _Seal,_ and, despite all his efforts, Garth could not shake her clear of the dying saurian. Once let her touch bottom with that great weight across her deck, and no power on earth could raise her again. “Sink her!” Garth cried at length, turning to his friend, “it’s our only chance. If we can’t get her clear of this brute we’re done.” Quick as thought Wilson darted below again, and a moment later the throb of the pumps broke upon the ears of the inventor. Would it be possible for the vessel to sink from under her monstrous burden?