POLYPS. 239 



wnich they are covered.- At length each becomes at- 

 tached to a rock, or shell, or sea-weed, and soon as- 

 sumes the form of the parent. If it be a kind which 

 buds, there soon grow from its sides or base others 

 exactly like itself, and from these, in turn, bud other 

 polyps of the same kind, and thus the community 

 goes on growing till it has reached its limits of in- 

 crease. If it be a kind which increases by division, it 

 widens as it grows upward, and at length the walls in 

 two opposite places begin to approach each other, and 

 soon the polyp is divided into two, so that there are 

 two mouths, and two circular disks surrounded by ten- 

 tacles, instead of one as before the division ; and the 

 polyps thus formed divide in the same way, and this 

 process is continued till from a single polyp there is 

 formed a large and beautiful cluster. 



Polyps readily reproduce lost parts, and even if cut 

 in pieces, each fragment will, in some cases, become 

 a perfect animal. Polyps vary in size from extreme 

 minuteness to those that are more than a foot across. 

 Some, like the Sea-Anemones, Figure 485, are wholly 

 soft ; others secrete a more or less solid framework, 

 which is called Coral; and those which secrete coral 

 are called Coral-Polyps, or Coral Animals. Some per- 

 sons suppose that coral is something that is built by an 

 insect, as the bee builds comb, or the wasp its nest, 

 and the industry of this supposed insect is often spoken 

 of. But it is' not proper to give the name insect to the 

 Coral-Polyps, for they are in no way related to insects, 

 either in appearance, structure, or habits. Coral is 

 not something which is built, but something which 

 grows. It is the skeleton, or many united skeletons, 

 of polyps, and these animals exhibit no industry in 



