66 NATURAL HISTORY READER. 



tion, and I saw its limbs escaping through every mesh of 

 the dredge. In my despair, I seized the largest piece, and 

 brought up the extremity of an arm and a terminal eye, 

 the spinous eyelids of which opened and closed with some- 

 thing exceedingly like a wink of derision." 



BUILDERS IN THE OCEAN. 



1. In the ocean within tropical regions are multitudes of 

 little sea-animals resembling the sea-anemone in structure, 

 known as coral polyps. They are made up of gelatinous 

 matter, and consist of a sack-like body with a mouth at 

 one extremity, surrounded by a row of radiating tentacles. 

 These tentacles reach out and grasp the food necessary for 

 the sustenance of the animal which the water brings. Un- 

 like the sea-anemone, the coral polyp is attached at one ex- 

 tremity to the rock, and has no power of movement save 

 the swaying of the body and the reach of the tentacles. 



2. This animal takes from the water not only food, but 

 it has the power of taking up the lime which is dissolved in 

 the water, and of reconverting it into a solid substance. 

 This lime is deposited in part at the bottom of its body 

 next the rock to which it is attached, and in part between 

 the tissues of the body itself. When the lime solidifies, the 

 part of the animal which incloses the hard mass dies, so 

 that coral is at once the framework and the tomb of the 

 polyp. 



3. Above the solid part the animal keeps alive, so that 

 the coral is constantly growing upward and outward. A 

 polyp with a single mouth multiplies itself by a kind of 

 budding. A small bunch will appear upon the side of its 

 body, which will soon develop into a perfect animal, wdth 

 mouth and tentacles complete, as in the original animal. 



