1328 THE STORY OF THE UNIVERSE 



spaces in the body, and they open into the central 

 stomach. The circles of these chambers are lined 

 with ciliate membrane, and in some places it is ar- 

 ranged in folds, and in them the eggs or ova form. 

 Little oval or roundish things, like pins' heads are 

 they: they burst forth and pass out of the stomach, 

 and then through the canal into the four lobes hang- 

 ing' down like pouting lips. Here they rest a while 

 until a little grown, and they start out on their jour- 

 ney of life in the autumn time as little oval or long 

 things made up of cells, the outside ones having mov- 

 able hairs also on them. Totally unlike the parent, the 

 tiny offspring floats off with the tide and does a little 

 work in moving itself with its hairy covering. Sooner 

 or later this minute thing, which is called a planula, 

 settles on a stone or piece of sea-weed, and begins 

 to grow. First of all its outer skin is formed into 

 a hollow on the top, a kind of basin-shaped cavity 

 being produced. This is the future stomach. Then 

 some little projections grow around the hollow, and 

 stick out in the water like so many rays, and they 

 increase in number and length very rapidly. Under 

 this shape the creature has been described as a hydra 

 or a polype, and it really resembles a small sea-anem- 

 one with very long and slender tentacles. But the 

 internal anatomy differs. The creature is all stomach 

 and tentacles, and it grows by catching small prey. 

 All the elaborate tissues of the jelly-fish are absent 

 and the creature can not move. It is this curious con- 

 dition of life that brings the jelly-fish tribe within 

 notice of a seashore observer, for those little hydras 

 live in some places at low-water mark. The knowl- 



