1 6 LIVING CREATURES. 



tables. Then it paddles around the obstacle, and 

 shoves itself away into the free water, asking help of 

 nobody. 



By and by this homeless infant settles down on the 

 sea-bottom with its mouth if a simple hole can be 

 called a mouth against the place where it is to be 

 fixed. It spreads out a thin, flat membrane which 

 drives out the water beneath it, and then it is held 

 down by the weight of the water above. Here it 

 grows into the little cavities of the bottom, attaches 

 itself firmly, becomes an adult sponge, and ever after 

 remains fixed, or until some fisherman lays his hand or 

 spear upon it. 



Far more absurd than the little waif with thread-like 

 legs is the stationary animal now to be explained. It 

 has no head, no tail, no legs, no arms, no eyes, no 

 ears, no real mouth, no stomach, no heart, no lungs, 

 no true blood. It never moves from its place, and yet 

 it is alive. It can not go in search of food, but expects 

 food to come in search of it. Fortunately, the rolling, 

 restless sea takes care of it. There is afloat in some 

 waters a mass of minute vegetables and animals so 

 small as to be seen only with the microscope. These 

 are the food brought to the sedentary sponge by the 

 motherly waves. 



The living sponge, like the living human body, has 

 its hard parts and its soft parts. The hard parts of 

 our bodies are chiefly bone ; taken together, we call 

 them the skeleton. The hard parts of the sponge are 

 this porous, springy article which is used on the slate 

 and in the bath. This is its skeleton ; and it is made 

 of fine, horny fibers. The soft parts of the animal 



