VEGETATIVE PROPAGATION 



327 



Vegetative Propagation and Regeneration in Zoophytes (Ccelen- 

 terata). — 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 o.'g'g. 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 {Siphonophord) 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 {Antkozoa), 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 



