NATURE STUDY IN SCHOOLS. 65 



opens into the gullet, or a kind of throat, which leads into the stomach. 

 The stomach is like a little bag and is in the center of the polyp. 



When any little sea animal, which the coral polyp wishes to eat, 

 comes within reach, the tentacles are extended to grasp it, and draw it 

 into the mouth, down through the gullet into the stomach. If there is 

 any part of the animal that the polyp does not care to eat, it is thrown 

 back into the water through the mouth. The polyp has no intestine or 

 any opening to pass off waste matter. 



The tentacles do not look to be a very important part of the polyp, 

 but they are most wonderful. They have little fine threads, called lasso 

 threads, on them and at the end of these little threads is a cell. When 

 the animal which the polyp wishes to eat comes within reach, the tenta- 

 cles throw out these threads, and the poison which is contained in the cells 

 affects the nervous system of the animal, causing paralysis. The animal is 

 then drawn into the mouth by the tentacles, through the gullet into the 

 stomach, and digested. 



There is a space between the stomach and the outer walls of the 

 polyp. This space is divided into little chambers by partitions, like 

 the lobes of an orange. There is a little hole in the end of each tenta- 

 cle, through which the water passes into the tentacle and flows through 

 into one of these chambers, and as there is a little hole in each partition, 

 the water flows through the hole and passes from one chamber to another. 

 The water can come in or go out of any tentacle. The little polyp uses the 

 oxygen in the water to help build up its system. This is the way he 

 breathes for he has no heart or lungs. 



The coral polyp produces its young in three different ways. The way 

 I am going to tell you about first is by budding. The star-fish, when it 

 loses a ray, buds another ; so the polyp does the same thing when it pro- 

 duces its young. It buds a little bud on its side that develops into a little 

 polyp, which does not leave the mother polyp but stays there. In some spe- 

 cies the polyp divides itself down through the middle, making two perfect 

 polyps where there was one before. 



The last way, common to all species, is by laying eggs. The eggs are 



formed in one of the lowest chambers, and are thrown into the water through 



the tentacles, as the tentacles are the only opening, or passage, into the 



water, from the chambers. The little egg stays in the water until it is hatched. 



When it is hatched it is a round, soft body covered with little arms or 

 legs called cilia, with which it can swim about very freely. 



It swims about until it finds a suitable place to fasten itself. For, 



small as the polyp is, it knows it cannot thrive in water deeper than one 



hundred and fifty feet. It will fasten itself by suction to a rock, shell or a 



skeleton of a dead coral animal, and then begin to build a skeleton for itself. 



