like
the bones of vertebrates, and is not built up as bees build a honeycomb
as is popularly believed. The pits or depressions on a branch of coral
represent the places where the coral colonists once grew. Coral is a
common subÂmarine feature in low latitudes all around the globe, but
the gem or precious coral, Corallium rubrum, formerly called Corallium nobile, comes
almost exclusively from the Mediterranean Sea off the African,
Corsican, and Sicilian coasts. A wild-rose pink is the particular shade
most highly favoured. The Corallium rubrum, the only species utilised and valued to any extent for jewelry, belongs to the family Gorgonidae of the group Alcyonaria.
The skeleton of a colony of Corallium rubrum is
found to be cemented firmly by a disc-shaped foot to any dense natural
or foreign object on the sea bottom, as a stone, cannon-ball, bottle,
or, as is recorded in one case of fact, a human skull. The branches
seldom exceed a foot in length and an inch in diameter. A curious
characteristic of coral is, that it grows always perpendicular, or
approximately, at a right angle to the surface to which it is attached—
downward, if its foothold is on the under face of a rock.
