112 THE BEAUTIES OF NATURE CHAP, 
alis, and Butterfly as stages in the life-history 
of a single individual. But among Zoophytes, 
and even among some insects, one larva often 
produces several mature forms. In some 
species these mature forms remain attached to 
the larval stock, and we might be disposed to 
regard the whole as one complex organism. 
But in others they detach themselves and lead 
an independent existence. 
These considerations then introduce much 
difficulty into our conception of the idea of an 
Individual. 
ANIMAL IMMORTALITY 
But, further than this, we are confronted 
by another problem. If we regard a mass of 
coral as an individual because it arises by 
continuous growth from a single egg, then it 
follows that some corals must be thousands of 
years old. 
Some of the lower animals may be cut into 
pieces, and each piece will develop into an 
