386 Shell Life 



in which the ink is produced, and a larger cavity 

 call the ink-reservoir in which a store of diluted ink 

 is kept always ready for use. A long tube connects 

 this with the neck of the funnel, its opening being 

 guarded by a double set of sphincter muscles. When 

 danger threatens a quantity of ink is discharged 

 into the funnel, and the rectum being forcibly 

 emptied the stream carries the ink into the sea 

 and surrounds the mollusk with an aqueous cloud, 

 under cover of which it makes off. The stream of 

 water from the funnel also has the effect of sending 

 the Cuttle quickly backwards through the water. 



Another important feature of these mollusks is 

 found in the spots of colouring matter with which 

 the skin is dotted. These pigment-spots are so 

 much under the control of the nervous system that 

 they can be instantly dilated or contracted at the 

 will of the animal. It is by this means that the 

 chameleon-like changes of colour are so rapidly 

 effected, and the creature so harmonised with the 

 hue of its immediate surroundings as to become 

 practically invisible. 



The sub-order Octopoda presents us with the species 

 most familiar to " the man in the street " by reason 

 of its frequent representation pictorially, and by 

 the presence of living examples in our large public 

 aquaria. In the quiescent condition they are very 

 unsightly creatures, the body consisting of a rounded 

 bag, above which stare the great eyes, whilst the 

 lono" arms coil about it in all directions. We have 

 two species. 



The Common Octopus (Octo2ms vulgaris) is chiefly 

 found alono: the south coast and in the Channel 



