Molluscs 153 



for hours beside a bivalve, slipping a 

 stone between the shells just as they 

 begin to open. The octopus, though 

 given to making a rock fissure its home 

 for months on end, is essentially a 

 wanderer, ever seeking fresh adventures, 

 and its restlessness may lead to em- 

 barrassing situations in the aquarium. At 

 Brighton, for instance, an octopus once 

 pulled up the waste plug of its tank at 

 closing time and condemned itself and 

 its tank-mates to spend fourteen hours 

 out of water. As a result the majority 

 of the inhabitants of the tank were found 

 dead in the morning. In the same 

 aquarium an octopus some years ago 

 climbed up the front of a tank, escaped 

 through a ventilator and landed upon a 

 lady visitor in the corridor below. In 

 most aquaria the octopus tanks are 

 generally roofed over with netting or 

 wire. Not long ago in a Continental 

 aquarium, where no such provision was 



