SOME MOOT POINTS Z.V XATURAL HISTORY. 



259 



in its subsequent history, may evolve the form of the highest 

 being, witli all the attributes of intellect and mind. 



A thoroughly popular mode of distinguishing between 

 animals and plants is that which credits the former with the 

 exclusive possession of locomotive powers, and which as- 

 sumes plants to present the ordinary aspect of stable and 

 rooted existence. But that animals are by no means uni- 

 versally endowed with powers of voluntary movement, is 

 proved by the consideration that very many of them exist in 

 a permanently fixed condition. The coral-polypes, zoo- 

 phytes, sea-mats, and sea-squirts, already mentioned, exem- 

 plify true animals which present exceptions to the ordinary 

 rule of animal life, in respect of their rooted state, and to 



. :. A group of lower animals and plants, all highly magnified, showing free- 

 swimming habits in both. Figs. a. to d inclusive represent lower forms of plant 

 life ; e to / represent forms belonging to the infusorian animalcules. 



this list the sponges and other animals might be added. 

 Neither, on the other hand, is it true that plants are invari- 

 ably fixed. The slightest acquaintance with the habits of 

 lower plants will show, indeed, that fixation is the exception, 

 and absolute freedom the rule ; very many of the lower 

 plants or algae (Fig. 42, a to d] swimming freely about in 

 their native waters during their entire existence. The 

 spores or germs of sea-weeds (a, />, c) present the closest 

 resemblance to animalcules, and propel themselves through 

 the water by means of the delicate filaments with which they 



