CHAPTER XIV. 



Ccelenterata. 



THIS group of very low forms of life contains the Jelly-fish, Sea Anemones, 

 and Corals. 



Jelly-fish. Most people have some passing acquaintance with these 

 strange creatures, if only from the sight of their shapeless masses on the 

 seashore ; but they possess many remarkable features, and in their native 

 element are beautiful objects, while their life-history is in itself of very great 

 interest. 



The Marigold (Aurelia aurita) is one of the commonest of the British species, 

 and may be known by the four crimson rings on its body. If one is examined 

 carefully in water, the disc will be seen to be divided into eight divisions, 

 marked off by eight tubes, each ending at the margin in a little notch, where 

 there is a very sensitive organ, possibly acting as nose and eye. It swims 

 by contracting and expanding its body. The four crimson rings are ovaries, 

 in which the eggs are produced. The young, when " hatched," swim away 

 as minute flat objects, propelled by cilia. They settle down on a rock and 

 change in form, hanging downwards, producing tentacles, and becoming 

 mere tubes of jelly, known as Hydra tuba, $ inch long. Later on this develops 

 into a form likened to a pile of saucers with serrated edges, and these float 

 off one by one, turn over, and become jelly-fish proper. Under the bell- 

 shaped disc there are a group of pendent organs, known as the manubrium or 

 handle, in the centre of which are four dangling, ribbon-like lobes surrounding 

 the mouth. 



The Sea Nettle (Cyanea chrysaora) is a large species found on the North 

 and East Coasts, with a disc marked by fine radiating brown lines. 



The Hairy Stinger (C. capillata] has a bulging disc, tawny coloured, and 

 with the foregoing species can " sting " that is to say, the long yellow threads 

 dangling from its body act like nettles, containing minute darts, answering 

 to the nettle's. These fringes of threads are in reality the fishing-lines by 

 which Jelly-fish catch their prey the fry of fishes, the zoe'as of shrimps and 

 prawns, etc. Each thread contains hundreds of cells, in each of which is a 

 tiny dart, coiled up like a spring, and these spring out at a touch, embedding 

 themselves in the body of their victim. Obviously persons with sensitive 

 skins should avoid contact with these species. 



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