VEGETATIVE PROPAGATION 



327 



Vegetative Propagation and .Regeneration in Zoophytes (Ccelen- 

 teratd). A simple case of budding is presented by the little 

 Freshwater Polype (Hydra] during the summer months (fig. 852). 

 A bud is formed by the outgrowth of a little projection from the 

 wall of the body, which later on develops a mouth 

 and tentacles, ultimately being pinched off from its 

 parent as a new individual. And by vigorous bud- 

 ding a small temporary colony may be produced. 

 The members of the group of Hydroid Zoophytes 

 {Hydromedusce), of which Hydra is a degenerate 

 representative, are typically colonial, each colony 

 resulting from the budding of a primary individual 

 developed from an egg. And many kinds of Jelly- 

 Fish are stages in the life-histories of such Zoophytes, 

 from which they bud off. 



The free-swimming colonies to which the name 

 Compound Jelly- Fish (Siphonophora) is given are also 

 the products of budding (see vol. i, p. 481), while 

 other kinds of Jelly- Fish come into existence as the 

 result of transverse splitting or fission of fixed individuals (see 



P- 352). 



Vegetative propagation is eminently characteristic of the 

 marine forms known as Sea- Flowers (Anthozoa), among which Sea- 

 Anemones and most Corals are included. The former are familiar 



Fig. 852. Bud- 

 ding Freshwater 

 Polype (Hydra), 

 enlarged. Two 

 buds are shown. 



Fig. 853. Vegetative Propagation of Sea- Anemones, diagrammatic 

 A, Longitudinal fission. B, Transverse fission, c. Laceration. 



objects at the sea-side, and do not form colonies. Budding is 

 known to take place in some species, but fission is a much com- 

 moner method of multiplication (fig. 853). When it takes place 

 a groove makes its appearance, which gradually extends right 

 across the Anemone, gets deeper and deeper, and ultimately 



