CHAP. IV.] ST. THOMAS TO BERMUDAS. 283 
of like reefs in the Pacific, with certain peculiarities depending 
upon the circumstances that it is the coral island farthest from 
the equator, almost on the limit of the region of reef-building 
corals. Accordingly, some of the great reef-building genera, 
such as Madrepora, Cladocora, and Astrangia, which are com- 
mon even in the West Indies, where the coral fauna is scanty, 
are absent. 
The water over the reefs is extremely clear, and by using a 
water-glass—a square bucket with the bottom of plate-glass, just 
lowered so far as to get rid of the ripple and reflections on the 
surface—every detail can be made out of the economy of the 
reefs, and that of their inhabitants. The reefs and ledges are 
of all sizes, and they are separated from one another by channels 
from a yard to a quarter of a mile in width, floored with white 
coral sand, the débris of the coral worn down by the action of 
the waves, mixed with dead shells. The reefs project abruptly 
above the level of the floors of these passages to the height of 
six to ten feet. The surface of the reef is covered with mass- 
ive, branching, and feathery things of very many kinds, occu- 
pying it as closely and as irregularly as the various weeds do 
a fallow-field. First we have the growing corals themselves, 
which may represent the dockens and the thistles, or rather a 
mass of beautiful marigolds and carnations, and daisies and ga- 
zanias, Which have been thrown over the hedge in clearing a 
luxuriant garden, and have taken root and gone on flowering. 
Most of the Bermudas corals, such as Oculina diffusa, Symphyl- 
lia dipsacea, Astrea radians, ete., are like sea-anemones or 
groups of sea-anemones in every shade of purple, orange, or 
green. The base or stock of the coral is dead, and forms part 
of the reef; but each of the living branches is tipped with its 
sea-anemone, and the stars of plates by which its cups are sup- 
ported are the earthy skeleton of the mesenteric plates which 
hang the stomach of the sea-anemone in its body-cavity. In 
most cases the bodies of these sea-anemones, with their ranges 
