ill ON ANIMAL LIFE 109 



Fig. 4 represents the Medusa or free form 

 of this beautiful species. 



If we pass to another 

 great group of Zoophytes, 

 that of the Jelly-fishes, 

 we have a very similar 

 case. For our first knowl- 

 edge of the life-history 

 of these Zoophytes we 

 are indebted to the Nor- 

 wegian naturalist Sars. 

 Take, for instance, the 

 common Jelly-fish (Me- 



dusa auHta) (Fig. 5) Of Fig. 4. Bougainvillea 



fruticosa, Medusa-form. 



our shores. 



The egg is a pear-shaped body (/), covered 

 with fine hairs, by the aid of which it swims 

 about, the broader end in front. After a 

 while it attaches itself, not as might have 

 been expected by the posterior but by the 

 anterior extremity (2). The cilia then dis- 

 appear, a mouth is formed at the free end, 

 tentacles, first four (j>), then eight, and at 

 length as many as thirty (^), are formed, and 

 the little creature resembles in essentials the 

 freshwater polyp (Hydra) of our ponds. 



