128 



THE HARMONIES OF NATURE. 



ducted. The body lengthens and becomes wider upwards, 

 tentacles form round the mouth (A) and then new buds sprout 



forth successively (B), which, 

 finally detaching themselves 

 from the parent stock(c), swim 

 about as perfect Medusae, 

 whose eggs in their turn are 

 destined to perform a similar 

 cycle of changes. Many ma- 

 rine animals, which, before 

 this wonderful alternation of 

 generations became known, 

 were reckoned among the 

 polyps, have now been found 

 out to be mere sessile forms 

 of AcalephaB, and future in- 

 vestigations will no doubt 

 considerably add to their 

 number, and point out the 

 nearest relationship or rather 

 the identity of many species, 

 still supposed to belong to 

 distinct orders of animated beings. 



The ribbed orCiliograde Jelly-fishes are distinguished from the 

 Discophora by their external generally globular or egg-shaped 

 form, and by their internal structure 

 and peculiar mode of progression. 

 While the Discophora move along by 

 propelling a jet of water against the 

 surrounding liquid, locomotion is here 

 produced by innumerable flat plates or 

 little paddles, attached to longitudi- 

 nal equidistant bands or ribs which 

 divide the crystalline body into equal- 

 ly large segments or fields. When 

 the animal wishes to swim backwards 

 or forwards, it sets all its paddles in 



motion, and glides rapidly and gracefully through the water 

 by their united power. When it wishes to turn, it merely 

 stops the movement of its paddles on one side. When these 



Medusa Larvae. 



Cydippe. 



