THE PACIFIC OCEAN. ONT 
(Meandrina), a flower-like Caryophilla, occupy 
the bottom. In the shallow hollows of the reef, 
Pocillopora verrucosa, a species having short waved 
plates or branches, is found: when alive it is a beau- 
tiful object, béing of a delicate pale crimson hue. 
Conflicting statements have been made respect- 
ing the activity of the building processes going on 
in the present age; some affirming that the reefs 
have acquired no perceptible addition, either to 
their height or extent, since they have been known; 
others anticipating a speedy filling up of the’ Pacific 
from their rapid growth. The truth seems to be, 
that, while in some localities no change in extent 
can be traced through many years, in others very 
rapid enlargements are made. As showing the rate 
at which coral grows under favourable circumstances, 
Mr. Darwin mentions two or three interesting cases. 
In the lagoon of Keeling Atoll, a channel was dug, 
for the passage of a schooner built upon the island, 
through the reef into the sea; in ten years after- 
wards, when it was examined, it was found almost 
choked up with living coral. Dr. Allan, at Mada- 
gascar, placed several masses of coral, of different 
species, each weighing ten pounds, in the sea three 
feet beneath the surface, where they were secured 
from removal by stakes. This was in December; 
and in the month of July following, they were found 
nearly extending to the surface, immovably fixed to 
the rock, and grown to several feet in length, A 
ship in the Persian Gulf, in the course of twenty 
months, had her copper encased with living coral to 
the thickness of two feet. 
2A 
