214 UTILIZATION OF MINUTE LIFE. 



dried in the sun, and packed in baskets, which sell 

 at a high price among the Asiatics. Long before 

 Polypes should likewise be placed the class of 

 Rotiferce, or wheel-animalcules ; but, on account of 

 their microscopic forms, the little I have to say 

 upon them will be found in the chapter on Infusoria. 

 The same remark will apply to some other micro- 

 scopic beings. 



Polypes comprise a numerous series of animals 

 that have been classed in the genera: Coralium, 

 Isis, Madrepora, Caryophyllea, Oculium, Pocillopora, 

 Astrea, Porita, Meandrina, Tubipora, Sertularia, 

 Actinia, Hydra, and a few others. They are wonder- 

 fully numerous. Nearly one-seventh part of the 

 actual crust of our globe is composed of the remains 

 of animals, and polypes contribute largely towards 

 this fraction of our present world. Several species 

 are valuable to us in different manners. 



The body of a polype appears most simple in its 

 organization ; it consists of a little gelatinous sack 

 or bag, the opening of which is surrounded by ten- 

 tacles. Some species live separately, floating about 

 singly in the water, or fixed one by one to the 

 rocks. Others live in large companies, and secrete 

 a curious habitation or basis, called a polypidom. 

 They have been therefore divided into two groups, 

 namely : Naked polypes, such as the Sea Anemones 

 and the Hydra of our fresh-water ditches and 



