CLASSIFICATION AND CREATION. 47 



the centre to the periphery. Cutting it across 

 transversely, or looking through its transparent 

 mass, the same radiation of the internal structure 

 is seen again ; only that in this instance the radi- 

 ating lines are hot produced by vertical partition- 

 walls, with open spaces between, as in the Polyps, 

 but by radiating tubes passing through the ge- 

 latinous mass of the body. At the periphery is a 



Melicertum seen from above, with the tentacles spreading : o o, radiating tubes 

 with ovaries ; m, mouth ; tttt, tentacles. 



circular tube connecting them all, and the tenta- 

 cles, which hang down when the animal is in its 

 natural position, connect at their base with the 

 radiating tubes, while numerous smaller tentacles 

 may form a kind of fringe all round the margin. 



The third and highest class includes the Star- 

 Fishes, Sea-Urchins, and Holothurians or Beches- 

 de-Mer. The radiation is equally distinct in each 

 of these ; but here again the mode of execu- 

 tion differs from that of the two other classes. 



