INTRODUCTION. 9 
After ten or twelve years of repose the branches have become 
a foot or sixteen inches long, and are again ready for the 
market. They vary much in price, according to the fineness 
of their tints and the compactness of their structure,—the 
finest bringing ten guineas an ounce, and the inferior ones 
not above a shilling a pound. 
These Mediterranean corals hold as it were a middle 
place betwixt our own tiny zoophytes, and the magnificent 
corals of the great Pacific Ocean. The rate at which the 
latter grow or increase in size has not yet been accurately 
ascertained, though it is a matter which bears on questions 
of considerable scientific importance. Some say that the 
reefs on which their operations are carried on do not grow 
above six inches in a hundred years; others again say that 
from their own observation they are convinced that they 
grow a foot in a few years. The truth, it is probable, lies 
between these statements. The rate of growth, as we have 
said, of Mediterranean corals, has been ascertained with 
considerable accuracy—not by scientific naturalists, but by 
rough sailors, who find it their interest to know how often 
their coral groves yield a fresh crop. Though the rate of 
growth of our native zoophytes is in many cases matter of 
uncertainty, yet as we find some of them a foot in height 
