AMPHIBIOUS FISHES. 



547 



" I therefore took pains to surround them with conditions analogous to those 

 they meet with when, after the water has retreated, the soil first becomes dry, 

 and then hardens. The water in the aquarium was drawn off little by little as 

 soon as the animals had burrowed into the mud. Three weeks had scaroely 

 passed, and already the hardened earth showed a number of cracks ; through 

 these a small quantity of air is admitted, which supports respiration. 



" On the seventieth day I examined the earth, and found that the two ani- 

 mals had met with such conditions as enabled them successfully to live through 

 the artificially-produced dry season : they were enveloped in cocoons, and were 

 full of life, as was shown by their motion on being touched ever so lightly. 



