390 ON THE GROWTH OF 



at all depths, under all degrees of pressure, and, so to 

 speak, in all temperatures. 



Another circumstance to which navigators have not ad- 

 verted, which corroborates the opinion here stated, is r 

 that, in depths so great as those to which we allude, the 

 sea, always agitated at the surface, breaks with force upon 

 these reefs, without requiring for that purpose any addi- 

 tional impulse from the winds. And by merely attend- 

 ing to the necessary consequences of the observations of 

 these same navigators, who say (what is very true) that, 

 wherever the waves are agitated, the lithophytes are un- 

 able to go on with their work, because they destroy their 

 frail edifices, we shall acquire the moral certainty that 

 these submarine steeps are not produced by these animal- 

 cules. But, in these same places, let there occur a hol- 

 low, a sheltered spot of some kind, and then they will im- 

 mediately raise then habitations, and will contribute to 

 diminish the little depth tKat already exists there. And 

 this is what may be seen in almost all the places where 

 an elevated temperature permits these animals to grow in 

 abundance. 



In the localities where the tides are sensi\>lp, their cur- 

 rents alone may sometimes form irregular canals between 

 the madrepores, without their ever being encumbered 

 with their species, from the twofold cause united, of 

 the motion and the coldness of the water ; while, on the 

 other hand, the flexible alcyonia are seen to multiply 

 there. 



When these geological dispositions are carefully ob- 

 served, we see that the zoophytes rise to the surface of 

 the waves, never beyond it \ after which the generation 

 which has attained thus far appears to die. It is de~ 



