ALTERNATION OF GENERATIONS. 215 



Thus far there appears nothing particularly strik- 

 ing or improbable in the history of the Medusae ; the 

 next stage, however, exhibits matter for our ' special 

 wonder/ 



The young Acaleph now throws off its animal 

 existence, and sinks into a plant or compound polype. 



The lower part of the body swells, and from 

 thence, what may be termed a stolen, is thrown out. 

 On the upper surface of the stolen one and even two 

 buds are often formed. ' As the bud enlarges it be- 

 comes elongated, and bends itself downwards to reach 

 the surface of the stone to which the elongated ex- 

 tremity adheres; after this the attached end is 

 gradually separated from the body of the parent. 

 When thus detached, a small opening presents itself 

 at its upper end, its interior gradually becomes 

 hollowed out, and cilia grow upon it, and tentacula 

 begin to sprout around the mouth, exactly in the 

 same manner as in the buds formed on the upper 

 surface of the stolens.' 



Thus, from a single bud numberless other buds 

 are formed, each being endowed with equally prolific 

 powers. If the parent be cut in half transversely, 

 the cut will close in, attach itself to some object, and 

 produce stolens and buds ! If cut longitudinally, and 

 the cut edges be allowed to touch each other, they 

 will again adhere, and exhibit no trace of their ever 

 having been divided. If the cut edges of each 

 division be not kept apart they will approximate and 



