The Polypidoms are found near the surface of the 

 water as well as in the greatest deptlis of the ocean i 

 some exist in parts where the light of the sun cannot 

 reach, and multiply to infinity, notwithstanding the 

 enormous pressure and extreme cold which they must 

 experience, at a depth of two or three thousand fa- 

 thoms. There are strong grounds to presume that 

 their growth is slow in proportion as they are im- 

 mersed in the w ater, and that at a thousand metres 

 from the surface of the sea, it would be one hundred 

 years before coral would attain the same growth as 

 when only a few metres of the fluid covered it. 



Polypidoms as well as plants vary with the climate 

 they inhabit; in the colder latitudes the Cellarias 

 and Sertularias only are to be found, with a few close- 

 woven sponges, and a small number of Alcyones. In 

 the neighbourhood of the volcanic isles of the polar 

 regions, or on those shores exposed to that marine 

 flow, which after being heated with the tropical sun, 

 has bathed the eastern coast of America, and then di- 

 rected its course to the western shores of Europe, you 

 meet with Corallinas, with Gorgonias and Isidias : the 

 two first multiply a little from 60 to 50 degrees of 

 northern latitude ; their numbers then increase to the 

 44th or 45th degree : Gorgonias with rampant stems, 

 Spongias, with loose tissue, brittle or elastic, and 



