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THE POPULAR SCIENCE MONTHLY. 



life, and a small bell (e), which, however, grows very rapidly, so 

 that the animal soon assumes the adult form, shown in Fig. 9. 



The life-history of this species of Cunina is given in the fol- 

 lowing diagram : 



( Hydra = Medusa < eggs. 



III. Cunina Octonaria. — Egg = Planula = { Hydra 



1 X 



Medusa < eggs. 



Hydra = Medusa < eggs. 



The ^g^ becomes converted into 

 a planula, this into a hydra, and 

 this into a medusa, exactly as in 

 the case of Liriope, except that the 

 case is complicated by the bud- 

 ding of new hydras, each of them 

 destined to become a medusa, from 

 the body of the hydra which hatch- 

 es from the Qgg, during its para- 

 sitic life, and before it becomes a 

 medusa. Each Liriope-egg pro- 

 duces only one adult, while the 

 number of adults which may be 

 derived from a Cunina Qgg is quite 

 large, although every individual 

 in the series ultimately becomes 

 an adult, and multiplies by sexual 

 reproduction. 



In another species of Cunina, 

 Cunocantha parasitica, a new com- 

 plication is introduced, for the hy- 

 dra which hatches from the egg 

 never becomes a jelly-fish, but 

 remains a parasite as long as it 

 lives, budding off other larvae 

 which grow up into adults. Its 

 life-history is like this : 



i Hydra = Medusa < eggs. 

 Hydra = Medusa < eggs. 

 Hydra = Medusa < eggs. 



If the hydras which are formed by budding were to remain as 

 hydras, like the one which hatches from the egg, and were to bud 

 off jelly-fish, we should have a life-history which is exhibited by 

 many species, and is shown in this diagram : 



Egg = Planula = Hydra x 



i„ , ( Medusa < eggs 



Hydra x \ 



Medusa 

 Medusa 



< eggs. 



< eggs. 



< eggs. 



