DIFFERENT WAYS OF SWIMMING 



in the water and back again, undulating like an elastic 

 blade, finding within itself the secret of its movement, 

 and so goes forward. It does not go very far, and soon 

 falls back; but, each time, it covers several yards in 

 a few repeated undulations, and has only to begin 

 over again to cover a considerable distance. 



Other fishes, of very different shape, act in the same 

 way, using their bodies directly. Such are the eels, 

 congers and murries, long, snake-like, flexible and 

 undulating, able to crawl over the bottom and to swim 

 in mid water by the same means. Here and there in 

 the tank are heaps of pebbles and debris, with spaces 

 between. Several large congers with dark shining 

 skin have taken up their abode there, and are almost 

 completely hidden, only their necks and watchful eyes 

 protruding. Occasionally one or other of them leaves 

 his shelter. His long cylindrical body comes out by 

 degrees, then he begins to swim. He moves forward 

 with a serpentine motion, winding his way through the 

 water, exhibiting an elastic suppleness, an elegance of 

 which snakes on land are incapable. So he progresses 

 easily, swiftly, moving his great black body every- 

 where, poking his nose in all directions, then returns 

 to hide again. Sometimes he seems to hesitate or stop, 

 then, to keep himself up, he uses his median dorsal 

 and anal fins only. They fold and contract along his 

 whole length. Then he goes on his way, continuing 

 his pliant movements, the harmonious twists and turns 

 of the serpentine mode of swimming of which alone 

 he is capable. 



These methods of swimming, numerous and varied 

 as they are, become even more so when we go beyond 

 the fishes to consider other aquatic animals, their 

 fellows and companions in the world of waters. 

 Organs and means are multiplied almost indefinitely, 

 and all end in one definite action, movement by 

 swimming. The tank, in which I am making my 

 observations, contains, besides its other inhabitants, 



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