JELL Y- FISH SEA -ANEMONES. 70 1 



manubrium are prolonged into long oral arms. The edges of each of these 

 fold together so as to form tubes. The mouth then closes and suckers are 

 developed along the inner surfaces of the tubes, through which alone 

 nourishment reaches the stomach. Very large prey, such as fLh, is often 

 captured by these Jelly-fish, and held fast by the oral arms while the 

 nourishment is sucked out of it. 



In many of these Jelly-fish, reproduction takes place by means of eggs 

 which develop in the reproductive chambers. These eggs usually develop 

 into Medusae, but, in the large family of the 

 Discophorse, to which our own Jelly-fish 

 belong, the larva which results from the egg 

 is a small spherical body covered with cilia, 

 and never grows into a Medusa direct. It 

 attaches itself to a rock or sea-weed (Fig. 9, 1), 

 develops tentacles, and lengthens out. Con- 

 strictions then begin to appear round its body : 

 the first just below the tentacles, and others 

 successively further down. The edges formed 



by the constrictions become lobed, and the i, Larva. S, Strobila. 



little creature, usually not more than an inch 



long, soon has the appearance of a series of saucers with lobed margins piled 

 one upon another, but increasing in size upward (Fig. 9, S). After a time 

 the whole structure breaks up, each detached disc developing later into a 

 Medusa, often of gigantic size. This curious process of a sexual multiplication 

 is known as strobilation, each series of developing young being a strobila, 

 which is the Greek for fir-cone. 



There is only one permanently attached form among these Medusae. This 

 is the Lucernaria, a very beautiful flower-like animal often found adhering 

 to sea- weed. 



The Anthozoa or flower-like animals, which form the next group of the 

 Scyphozoa, include the stationary Sea-anemones and the Corals, the living 

 bodies of both of which are built on essentially the same 

 plan. The body of the Sea-anemone, however, always re- The Anthozoa. 

 mains soft, while that of the Coral proper develops a hard 

 skeleton. For this reason the Sea-anemones have been called the Fleshy 

 Corals, while one large division of the Corals is cilled the Stony Corals, on 

 account of their stony skeletons. The Sea-anemones always remain single, 

 while the Corals comprise both single and colonial forms. 



The Sea-anemone is a familiar object to most of us, as it is very plentiful 

 on our rocky shores. Small, coloured, jelly-like masses are often to be seen 

 adhering to the rocks at low tide, which, as soon as they 

 are again covered by water on the return of the tide, The Sea-anemones 

 expand in beautiful and brilliantly-coloured flower-like (Actinia). 



animals. Looking down upon an Anemone, the central 

 mouth can generally be made out fringed with its tentacles. If the body 

 were cut across a little below the level of these, we should find that it con- 

 sisted of two tubes, one within the other. The inner tube is the stomach 

 tube or oesophagus, lined with the outer skin, which, as above described, 

 characterises all the Scyphozoa. It is united to the wall of the outer tube, 

 which is the body wall of the Anemone, by a number of fleshy partitions, 

 which, running right through the length of the body, divide it up into many 

 compartments. The uppermost portion of each of these compartments runs 



