STAR-FISHES AND SEA-URCHINS. 63 



cle of food to the Chinese. They call it the Trepang, 

 and they send every year large fishing fleets to the 

 islands in the Pacific, and to the coasts of New Hol- 

 land, for the express purpose of collecting it. When 

 dried and preserved in a particular way, they find it a 

 great delicacy, though I doubt whether you or I would 

 like it very much. 



As there is one general name, that of Polyps, in- 

 cluding all animals of the kind which I first described, 

 like the Sea-Anemone, and another, that of Medusa 

 or Acalephs, including all of the second kind, like the 

 Jelly- Fishes, so there is also a general name for all ani- 

 mals like the Star- Fishes, Sea- Urchins, and Sea-Cucum- 

 bers, that of Echinoderms. Each of these, the Polyps, 

 the Acalephs or Medusae, and the Echinoderms, form 

 what is called by naturalists a class, and these three 

 classes are included under another name, that of Radi- 

 ates. In other words, Radiates form one great division 

 of animals, embracing Polyps, Acalephs or Medusae, 

 and Echinoderms. Now, if you look in your diction- 

 ary for the definition of the verb " to radiate," you 

 will find this : " To send out rays from a centre." This 

 explains the structure of all the animals belonging to 

 this division, and the reason why they are called by 

 this name. Whether they are round or long or star- 

 shaped, they are all so constructed that their parts 

 diverge from a centre ; and at that centre is an open- 

 ing, which is the mouth. 



This is the end of my stories about Radiates, deal 

 Lisa and Connie ; and I hope you will forgive this little 



