THE ANIMAL KINGDOM. 65 



All this time was necessary to prove that it is only the 

 production of a simple marine polyp, and that in the depths 

 of the seas which it inhabits, and from whence the fisher- 

 men tear it up with their nets, it is as hard as when it is 

 fashioned into those bracelets and rich necklaces which 

 form such a charming contrast with the white skins of our 

 most attractive women. 1 



CHAPTER II. 



ISLAND BUILDERS. 



UNSEEN by human eye, myriads of animals, more numer- 

 ous than the cloud of stars in the Milky Way, labor silently 

 in the depths of the sea, and build up structures the size of 

 which astounds us. Their erections, to which is commonly 

 given the name of coral reefs, are sometimes raised with 

 surprising rapidity, making parts of the ocean unnavigable 

 which vessels had previously gone through under full sail. 



These submarine banks are nothing but agglomerations 

 of the calcareous homes of polyps, constructed by fragile 

 animals not unlike minute flowers, and which inhabit the 

 innumerable little holes wherewith the surface is over- 



1 The natural history of coral has been completed quite recently by M. Lacaze- 

 Duthiers. This zoologist observed that the individuals scattered over the 

 branches of the polypoid imitate in their sexual disposition an arrangement seen 

 in certain plants. Some are only males; others carry only female organs; lastly, 

 there are some which bear both sexes at the same time, and are hermaphrodite. 

 The eggs of the coral are spherical and of a milk-white color, and very soon after 

 they have issued from the body of the mother move about actively and seek out a 

 favorable site to plant themselves upon. 

 5 



