146 The Under-Water World 



of their bodies than those of almost any 

 other animal. The molluscan foot, used 

 by the snail to crawl, and by the cockle 

 to jump, is split into eight or ten arms 

 each beset with several hundred suckers. 

 Each sucker is rimmed with a horny ring 

 and can exert a pull with a pressure of 

 anything up to 30 lb., according to the 

 size of the animal. It must therefore 

 be admitted that a creature furnished 

 with nearly 3,000 such suckers can be 

 no mean antagonist. If we add to this a 

 marvellous capacity for changing colour, 

 enormous energy, with great tenacity of 

 life and the power to cover a retreat by 

 means of a smoke-screen, it will not 

 come as a surprise to learn that the 

 Cephalopods have survived in large num- 

 bers from an early age. The octopus 

 and cuttle-fish are hatched from eggs 

 known to fishermen as sea-grapes, and 

 these are usually attached to weeds. 

 Unlike most mollusca, the young pass 



