THE CREATURES OF THE SEA. 13 



prominent head, with big, staring eyes, and a beak 

 like a parrot's, which is surrounded by a circle of 

 arms or tentacles, set with many hooks or suckers. 

 While they sometimes crawl on the bottom of the 

 sea, most of them can swim freely, if they wish to, 

 and they have a comical habit of pouring out a 

 quantity of black ink to darken the water when 

 they wish to hide or escape from some enemy. 

 They are called Ceph-al-o-pods, from two Greek 

 words meaning head and foot, because they some- 

 times use the arms on. their heads as organs for 

 walking. 



The second class have very small eyes set on 

 little stalks, and their mouths have neither beaks 

 nor suckers, but a curious tongue clothed with 

 very numerous little hooked teeth. They cannot 

 swim, but they lie flat on the rocks, and creep 

 along very slowly by means of little muscles in a 

 disk or foot which forms the lower part of the 

 body. When they stop moving they can hold on 

 like a sucker, and so they can resist the force of 

 the waves. 



They are called Gas-ter-o-pods, because they 

 creep, as it were, upon their stomachs. All the 

 snails belong to this class. Most of the Gastero- 

 pods are protected by a single shell, usually spiral 

 in shape, though there are plenty of slugs, both 



