590 THE REPRODUCTIVE FUNCTIONS. 



process is analogous to the natural mode of mul- 

 tiplication met with in the lower orders of Zoo- 

 phytes, such as the Hydra. At the earliest 

 period at which the young of this animal is 

 visible, it appears like a small tubercle, or bud, 

 rising from the surface of the parent hydra : it 

 grows in this situation, and remains attached for 

 a considerable period ; at first deriving its nou- 

 rishment, as well as its mechanical support, 

 from the parent ; then occasionally stretching 

 forth its tentacula, and learning the art of catch- 

 ing and of swallowing its natural prey. The 

 tube, which constitutes its stomach, at first com- 

 municates by a distinct opening with that of its 

 parent : but this opening afterwards closes ; and 

 the filaments by which it is connected with the 

 parent becoming more and more slender, at 

 length break, and the detached hydra imme- 

 diately moves away, and commences its career 

 of independent existence. This mode of multi- 

 plication, in its first period, corresponds exactly 

 with the production of a vegetable by buds ; 

 and may therefore be classed among the in- 

 stances of gemmiparous reproduction ; although 

 at a later stage, it differs from it in the complete 

 detachment of the offspring from the parent. 



Another plan of reproduction is that in which 

 the germs are developed in the interior of the 

 animal, assuming, at the earliest period when 

 they become animated, the form of the parent. 



