CHAPTER XVIII.
A few moments later he sent a signal to Murgatroyd in the engine-room.
The propellers began to revolve slowly, beating the dense air and driving the _Astronef_ at a speed of about twenty miles an hour through the depths of this strangely peopled ocean.
They approached nearer and nearer to the surface, and as they did so the uncanny creatures about them grew more and more numerous.

They were certainly the most extraordinary living things that human eyes had ever looked upon.

Zaidie's comparison to the whale and the jelly-fish was by no means incorrect; only when they got near enough to them they found, to their astonishment, that they were double-headed--that is to say, they had a head with a mouth, nostrils, ear-holes, and eyes at each end of their bodies.
The larger of the creatures appeared to have a certain amount of respect for each other.

Now and then they witnessed a battle-royal between two of the monsters who were pursuing the same prey.

Their method of attack was as follows: The assailant would rise above his opponent or prey, and then, dropping on to its back, envelop it and begin tearing at its sides and under parts with huge beak-like jaws, somewhat resembling those of the largest kind of the earthly octopus, only infinitely more formidable.