FORGES. 



171 



Fig. 244. — VdtlUneria ^iralis (Eel-grass): 

 male plant ; b, male plaat. 



the higher plants, for these are fixed in the earth, whilst the zoospore 

 floats free in water, with nothing to restrict its motions. 



418. Voluntary Motion is defined as action done from 

 choice by the will (L. 

 voluntas, will or choice). 

 Like sensation, it pre- 

 supposes the existence 

 of nerves, and still 

 more of nerve-centres, 

 or brain, and therefore 

 Mind, or its lower ex- 

 pression. Instinct 

 Plants have neither 

 nerves nor brain, yet 

 much of their behavior seems as voluntary as the lying- 

 in-wait of a spider to entrap a fly, the sport of kittens in 

 the sunshine, or even the loves of human beings. The 

 common Eel-grass (Fig. 244), a well-known inhabitant 

 of clear, still water or slow-running streams, is dioecious. 



The male and female plants, 

 however, always grow near 

 each other. The flowers 

 are produced under water. 

 The females grow singly, 

 each on a long peduncle, 

 which twists spirally (Fig. 

 244, a). The males, which 

 are minute, are sessile on a 

 spadix with a peduncle so 

 short that they must remain 

 below water unless detached 

 from the spadix (Fig. 244, 

 b). Both males and females 

 develop under water ; when 

 ready for fertilization, the 

 females slowly uncoil their 

 long peduncles and rise to 

 the surface; the male 

 flowers at the same time detach themselves voluntarily 

 from the spadix, and each rises separately to the surface. 



