HABITS OF CERATODUS 



in order to ascertain the facts. It is only in Queens- 

 land that Ceratodus is met with. In the Mary and 

 Burnett rivers it occurs in deep quiet pools, which are 

 full of water in wet and dry seasons alike. Some per- 

 sons, impressed doubtless with the real likeness which 

 this " fish " bears to the amphibia, have asserted that 

 it basks in a crocodile-like fashion upon logs. The 

 Ceratodus, however, cannot leave its native streams ; 

 and instead of showing the least trace of an amphibious 

 way of life, it dies with peculiar ease when removed 

 from the water. It is probable, thinks Professor Bald- 

 win Spencer, that a large water lizard, common in and 

 along the banks of the same rivers, is responsible for 

 the stories of the Ceratodus basking upon tree trunks. 



With the laudable view of preserving so far as possible 

 this interesting survival from a bygone age, steps have 

 been taken in Australia to transfer this fish to other 

 rivers, where it apparently does well. Our descendants 

 may find that if these experiments continue to be suc- 

 cessful, the Ceratodus may lose some of its peculiarities. 

 At present the rivers in which it swims are not quite 

 ideal as fish reservoirs. During the hot weather ill 

 weeds grow apace, and also decay : there results a foul- 

 ing of the water and a concomitant lack of pure air, 

 and an increased difficulty for the Barramundi to 

 breathe. Nature, however, though a strict economist, 

 invariably permits, or rather insists upon, the wind 

 being tempered to the shorn lamb. The dyspnoeic 

 Ceratodus has, in consequence of these difficulties, 

 acquired a swim bladder which performs the offices 

 of a lung, instead of being merely, as in other fish, a 

 hydrostatic apparatus The lung has its own special 

 artery and vein exactly as in other creatures with lungs, 

 and the fish comes to the top of the water to inhale air, 

 just as any land-frequenting but occasionally aquatic 

 and diving animal does. In addition to this, it has the 



300 



