468 THE OCEAN WORLD. 



immortal author of the first Natural History of Animals, the philo- 

 sophical Aristotle. "The Nautilus Polyp," says the learned his- 

 torian, " is of the nature of animals which pass for extraordinary, for 

 it can float on the sea ; it raises itself from the bottom of the water, 

 the shell heing reversed and empty, hut when it reaches the surface it 

 readjusts it. It has hetween the arms a species of tissue similar to 



v 1 



that which unites the toes of web-footed birds. When there is a little 

 wind, it employs this tissue as a sort of rudder, letting it fall into the 

 water with the arms on each side. On the approach of the least 

 danger it fills its shell with water, and sinks into the sea." 



Pliny gives it the name of Pompylius, and, after the example of 

 Aristotle, explains how it navigates, by elevating its two first arms, a 

 membrane of extreme- tenuity stretching between them, while it rows 

 with the others, using its median arm as a rudder. The Greek 

 poet, Oppian, who lived in the second century of our era, and to whom 

 we are indebted for Poems on Fishing (Halieutica) and the Chase 

 (Cynegetica)., says of it : " Hiding itself in a concave shell, the Pom- 

 pylius can walk on land, but can also rise to the surface of the water, 

 the back of its shell upwards, for fear that it should be filled. The 

 moment it is seen, it turns the shell, and navigates it like a skilful 

 seaman : in order to do this, it throws out two of its feet like antennae 

 between which is a thin membrane, which is extended by the wind 

 like a sail, while two others, which touch the water, guide, as with 

 a rudder, the house, the ship, and the animal. If danger approaches, 

 it folds up its antennae, its sail, and its rudder, and dives, its weight 

 being increased by the water which it causes to enter the shell. 

 As we see a man who is victor in the public games, his head circled 

 by a crown, while vast crowds press around, so the Pompylius have 

 always a crowd of ships following in their track, whose crews no 

 longer dread to quit the land. fish justly dear to navigators ! thy 

 presence announces winds soft and friendly :. thou bringest the calm, 

 and thou art the sign of it." 



Oppian carried his admiration a long way. That the Argonaut is 

 an animated skiff is agreed on all hands ; but, in making it almost a 

 bird in according to it at once the faculty of gracefully navigating 

 the sea and floating in the atmosphere as an inhabitant of the regions 

 of a i r h e wa g passing the limits permissible to poetic license. 



But the properties of the Nautilus has not alone struck the ima- 



