CHAPTER III. 



Porifera {Sponges). 



What is an animal 1 Nothing seems easier than to 

 answer this question. Our thoughts in a moment recall 

 the image of the stately horse shaking his neuk of thunder, 

 and projecting columns of vapour through his translucent 

 nostrils ; or the painted tiger crouching in the jungle, 

 awaiting in lithe readiness the approach of some unconscious 

 antelope to make his mortal spring ; or the trembling 

 antelope itself, as it pants, and struggles, and groans 

 beneath the fangs of its merciless foe. Nothing appears 

 simpler than to define an animal. A being with head, and 

 body, and limbs ; full of energy and vigour ; possessed of 

 various instincts • master of many ingenious contrivances 

 all helpful to its peculiar economy ; executing various 

 movements ; manifesting intelligence in different degrees, 

 and governed by a wayward will. 



True, such a creature as this is an animal ; but are 

 there no animals but such as possess these characteristics? 

 Let us enumerate a few familiar instances. Look at the 

 ferocious crocodile. Is this an animal 1 " Without doubt," 

 you answer. The serpent, the frog, the mackerel? 



