78 MOKMYEIM. 



they take a gulp of air into their lung-like swim-bladder and fall again to the bottom 

 on reaching which they again start for the surface with unceasing regularity, so that 

 when looked at from above the nest of Gymnarchus, with its swarm of scarlet-bearded, 

 yolk-hampered larvae, presents a most amazing spectacle. 



" By the time the huge yolk-sac has been completely absorbed, the young larvae are 

 ready to leave the nest. They still, however, continue their ceaseless journeyings to 

 the surface for air. It may now be noticed, however, that the passage back to the 

 bottom of the nest is not merely a passive falling, but that the young larvae actually 

 dart backwards from the surface. When the young Gymnarchus leaves the nest it has 

 fully developed the characteristic cylindrical tail of the adult, and in this connection 

 its habits are very interesting. 



" The Gymnarchus propels itself through the w r ater, not by the action of its paired 

 fins, not by the motion of the axis of its body, but entirely by the action of its dorsal 

 fin. When Gymnarchus starts forwards, the motion is the result of a series of waves 

 passing backwards along the dorsal fin. About five such waves are passing at a time. 

 Suddenly the fish will proceed at the same rate in the opposite direction, and now the 

 motion is the result of a series of waves passing forwards along the dorsal fin. As the 

 Gymnarchus swims rapidly backwards in this way, it may be seen to guide itself through 

 the grasses by using this peculiar tail which it possesses as a feeler. Thus it appears 

 to be quite immaterial to the fish which way it progresses, and it always appears to 

 swim in comparatively straight lines. 



" How Gymnarchus constructs the wonderful floating nest in which it lays its eggs I 

 have been unable to observe. The natives approach these nests with great caution, 

 stating that the parent is at this time extremely fierce and has a very formidable bite. 

 Both the adult fish and its eggs are greatly sought after as food. 



"A large number of the young fry of Gymnarchus, which I had caught immediately 

 after they left the nest, lived well on chopped-up worms. I tried to bring some of 

 them to England alive, but every one died as we got into colder climes." 



