584 



THE POPULAR SCIENCE MONTHLY. 



asexual multiplication by buds, and tbe sign < sexual reproduc- 

 tion by fertilized eggs : 



I. Dysmorphosa. 

 Egg=Planula=Root x - 



Feeding hydra x 



X 



Feeding hydra x 



X 



Feeding bydra x 

 Feeding hydra x 



X 



Feeding hydra x 



X 



^ Feeding hydra x 



( Feeding hydra, 

 ■| Blastostyle x ■ 

 ( Fighting hydra, 



i Feeding hydra, 

 -j Blastostyle x ■ 

 ( Fighting hydra, 



i Feeding hydra, 

 Blastostyle x ■ 

 Fighting hydra, 



i Feeding hydra, 

 Blastostyle x • 

 Fighting hydra, 



Feeding hydra, 

 Blastostyle x • 

 Fighting hydra. 



Feeding hydra, 

 Blastostyle x • 

 Fighting hydra. 



Medusa 

 Medusa 

 Medusa 

 Medusa 

 \ Medusa 

 ) Medusa 



1 Medusa 

 Medusa 

 Medusa 

 ] Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 

 Medusa 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



< eggs. 



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< eggs. 



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The Qigg hatches into a planula, which becomes attached and is 

 converted into a root, from which feeding hydras hud ; from the 

 roots of these feeding hydras, other feeding hydras, and, after a 

 time, defensive hydras and blastostyles or reproductive hydras, are 

 budded in very great numbers, and, while the diagram correctly 

 represents the complexity of the colony, it conveys no conception 

 of its size or of the number of its members. Each blastostyle pro- 

 duces a considerable number of buds, which are ultimately set free 

 as swimming jelly-fish or Medusae, and each medusa multiplies by 

 budding, and thus gives rise to a second generation of Medusae, 

 which probably repeat the process in their turn, so that a very 

 great and practically unlimited number of sexual egg-producing 

 adults results from a single Qgg. 



What a contrast between the direct and simple history of ordi- 

 nary animals, where each adult is the total progeny of the Qgg, 

 and such a life-history as this, where the <dgg not only produces an 

 unlimited number of sexual adults able to bud off others like 

 themselves, but also gives rise to an innumerable number of larvae 

 which never become sexually mature nor assume the adult form. 



Those who are familiar with the subject know how much paj^er 

 and ink have been wasted in discussing the individuality of hy- 

 droids, but we need not enter into into this dead issue, for, beyond 

 question, each feeding hydra, each defensive hydra, each blasto- 

 style, and each jelly-fish is an individual in the same sense that a 

 horse or a dog is one ; and the most remarkable peculiarity of 

 Dysmorphosa is the enormously great number of descendants from 

 each Qgg. Another peculiarity must also be noted. The life-his- 



