146 From Matter to Man. 



from them, and the animal through a deathless 

 resurrection revives as a vegetal. 



In cedogonium, one of the fresh- water algae, swarm- 

 spores originate by "rejuvenescence." Thus an adult 

 cell contracts, changes from the cylindrical to the 

 globular shape, shoots out vibratile cilia, ruptures its 

 cellulose wall, escapes as a swarm-spore, enjoys for a 

 time the free life of an animal, but eventually rests, 

 becomes paralysed, and grows into a plant. 



(c) Antherozoids. — In those cryptogamic plants 

 which generate sexually, the female element is called 

 the spore, the male the antherozoid or spermatozoid. 

 In the marine alga {funis vesiculosus) the antherozoid 

 is an ovoid body with two vibratile lashes, and very 

 active. In ferns and horse-tails (equisetuni) the 

 antherozoid is wound like a cork-screw and provided 

 at its anterior part with quite a number of long 

 vibratile cilia. Mosses and charce generate similar 

 antherozoids, rolled like a helix and furnished with 

 two vibratile cilia. In all respects nothing essential 

 distinguishes these motor cilia of cryptogamic seed 

 elements from the cilia of the zoospores of the pro- 

 tozoic radiolarians. 



In many spores the strange phenomenon termed 

 " alternation of generations " is witnessed. Here we 

 see the curious anomaly of an organism transforming 

 through a series of animal and vegetal moults, until 

 it ultimately reverts to the parent type of plant. It 

 is, in fact, the first appearance on the stage of life of 

 the important phenomenon of metamorphosis, so 



