i86 



THE FLOATING ANIMALS 



like material. Others drop the tail and notochord on 

 assuming the adult form ; of these Pyrosoma (Fig. 149), 

 brilliantly luminous, as its name " fire-body " implies, 

 is a colony of animals embedded in a common cylinder 

 of jelly, mouths outwards. A solitary form, Doliolum, 



Fig. 140. Fig. 141. 



Fig. 142. 



Fig. 143. 



Fig. 144. 



Fig. 140.- 

 Fig. 141.- 

 Fig. 142.- 

 Fig. 143.- 



PlG. I44.- 



Fig. 145.- 

 FlG. 146.- 

 Fig. 147.- 



Fig. 145. 



Fig. 146. 



Fig. 147. 



-Auricularia Larva of a Holothurian. 

 -The same later, the young Trepang showing. 

 -Pluteus Larva of an Echinoid. 

 -The same later, the young Sea-Urchin promi- 

 nent. 

 -Bipinnaria Larva of an Asteroid. 

 -The same later, carrying the young Starfish. 

 -Pluteus Larva of an Ophiuroid. 

 -The same later, with the young Brittle-Star. 

 (Modified from Johannes Miiller.) 



is remarkable for its complex life-history ; the form, A, 

 (Fig. 150) itself developed from a fertilized egg, gives 

 rise to little buds, which wander up on to the projecting 

 horn behind their parent, and arrange themselves in 

 three rows. Those of the side rows, B, grow into a 

 spoon-shape, and act as food and water pumps for the 



