72 NATURAL HISTORY READER. 



a time when the countries which now shut Switzerland 

 from the sea did not exist, and her western boundary was a 

 sea-shore where corals built their reefs and shells lived on 

 the beaches. When you learn something about the forma- 

 tion of mountains, you will see how such beaches may be 

 raised from their natural level, so that the shells of animals 

 which lived upon them are found at last among the mount- 

 ains. On arriving in America, Mr. Agassiz began the study 

 of the jelly-fishes, star-fishes, sea-anemones, and like objects 

 living along our northern shore — animals which he had 

 never before had the opportunity of watching alive. And, 

 among other things, he became deeply interested in study- 

 ing the structure of the little corals found about Martha's 

 Vineyard Sound. 



5. He procured living specimens, kept them alive in 

 glass jars, changing the water frequently, and watched 

 them during a whole summer, having drawings made from 

 them to show the different parts of their body, their ap- 

 pearance when open or closed, and, in short, all the details 

 of their structure. Thus it happened that he was quite 

 familiar with these corals of our coast when he was invited 

 by Professor Bache, then Superintendent of the Coast Sur- 

 vey, to make an examination of the coral-reef of Florida, 

 in order to ascertain certain facts about it, the knowledge 

 of which was important to the interests of navigation. 



G. While making this survey he had, of course, the best 

 opportunity for studying the animals themselves. He ar- 

 ranged a working-room, or laboratory, at Key West, and 

 provided himself witli a number of glass jars and large glass 

 tubs, some of them so wide and deep that he could keep in 

 them masses of living corals measuring two feet in diame- 

 ter, completely immersed in water. This is a, necessary 

 condition. If you take a coral out of the water, he dies. 

 There are some kinds so sensitive that, merely m order to 

 take them from the sea and drop them into your jar, you 



