THE LUNGFISH 73 



with a pointed stick, and, if the end of the stick smells 

 of fish, disinter the victim. It grows to a large size, a 

 specimen in the Nairobi Museum being seven feet long 

 and weighing ninety poimds, though the majority of 

 specimens range up to only two to three feet. It is much 

 more elongated than most of its Devonian ancestors, 

 having somewhat the appearance of a large eel, while 

 its paired fins have lost all the ancient crossopterygian 

 characters and are reduced to long filaments which it 

 uses only for balancing. In water, Trotopterus hves very 

 much as any other fish, except that it rises to the surface 

 at ten- to fifteen-minute intervals to empty its lungs and 

 gulp fresh air, which is passed into the lung by swallow- 

 ing; the excess escapes from the mouth after the fish 

 sinks below the surface. It lives chiefly on snails, the 

 shells of which it can easily crush with its flat teeth and 

 powerful jaws. 



The equatorial region of Africa is subject to heavy 

 spring rains which alternate with protracted periods of 

 aridity. The severity of the annual rain is itself subject 

 to cycles that correlate with climatological changes else- 

 where in the tropics and are probably related to the 

 well-known eleven-year sunspot cycle. Consequently 

 during periods of light rainfall large areas along the 

 shores of the lakes and rivers may remain exposed as 

 mud flats for several years, receiving only a superficial 

 wetting in the rainy season. We had hoped to study the 

 estivating fish in its native habitat but, ignorant of the 

 eleven-year cycle in the rains, we found the coimtry 

 flooded and offering no hope of dry mud for several 

 years. This was, in a way, fortunate, because it forced 

 us to bring active fish back to New York where they 

 could be studied imder controlled laboratory conditions 

 for a period of several years. Small specimens, up to a 

 foot or more in length, were readily collected for export 

 from among the papyrus roots at Kisumu on the eastern 

 shore of Lake Victoria. The fact that petrol and oil are 

 imported into Central Africa in five-gallon and one- 



