DWELLINGS. I S3 



can thus easily come and go and retire into its cave, 

 where it finds security and a humidity favourable for 

 branchial respiration. From time to time it cleans 

 out the dirt and rubbish which accumulate in the 

 hole. It makes a little pile of all the refuse which it 

 finds, and, seizing it between its claws and abdomen, 

 carries it outside. Executing several journeys very 

 rapidly, it soon clears out its dwelling. 



The dipnoid Protopterus, which inhabits the 

 marshes of Senegal and Gambia, is curious in more 

 than one respect Firstly, it can breathe oxygen, 

 whether, like other fish, it finds it dissolved in water 

 or in the atmospheric air. When during the summer 

 the marshes in which it lives dry up, it takes refuge 

 in the mud at the bottom, which hardens and im- 

 prisons it, and it thus remains curled up until the 

 time when the water after the rainy season has 

 softened the earth which surrounds it. This fact had 

 been known for some time ; travellers had brought 

 back lumps of dried earth of varied size, the largest 

 about as big as two fists. On opening them the 

 same fish was always found within, and the chamber 

 in which it is contained was lined with a sort of 

 cocoon, having the appearance of dry gelatine. 

 Dumdril was able to observe one of these animals 

 in captivity. At the period corresponding to the 

 dry period of its own country, the Protopterus buried 

 itself in the mud which had been placed at the bottom 

 of the aquarium. In order to realise the conditions 

 found in nature, the water which covered it was 

 gradually withdrawn. The earth hardened in drying, 

 and when broken the recluse was seen surrounded by 

 hardened mucus, exactly like those which came from 

 Senegal. 



