LOW LIFE IN THE SEA. 71 



ranean, ho could keep his specimens alive, and study them 

 in their natural condition. He made his investigations 

 upon corals, as well as upon what are called Hydroids. 

 This name is given to a variety of small animals most of 

 which live in communities. The facts discovered by Peys- 

 sonel were so interesting that naturalists began to feel, as 

 they had never felt before, the importance of studying these 

 seemingly insignificant creatures, and of studying them 

 alive in their natural element. Since then a vast deal has 

 been learned about them ; and it was in the course of these 

 researches that the corals were found to be allied with all 

 the radiated animals, to have essentially the same structure 

 as the sea-anemones, star-fishes, sea-urchins, and countless 

 smaller animals belonging to the group of Hydroids. 



3. In learning about the corals, we ought to know some- 

 thing about the men who have taught us the most about 

 them. The first who studied the coral islands of the Pacific 

 was Charles Darwin, the great English naturalist, and he 

 wrote a charming and excellent book concerning them upon 

 his return home from the exploring expedition in the ship 

 Beagle around the world. Professor Dana, of Yale College, 

 who accompanied the United States exploring expedition, 

 made corals his especial study, and published an elaborate 

 and valuable book concerning them, which is now consid- 

 ered an authority. And, lastly, Milne-Edwards, the French 

 naturalist, though he has not had the living specimens be- 

 fore him, has taught us more than any one else of the hard 

 parts of these animals — that is, of those portions of their 

 structure which after their death are still preserved in the 

 solid masses built by them. 



4. Until he came to this country, Mr. Agassiz, like 

 most European naturalists, had lived far from the sea-shore. 

 It is true that in the heart of Switzerland he had gathered 

 marine shells and corals, and had studied them ; but they 

 were the dead shells and corals of past ages, belonging to 



