As we row, keeping watch ahead, the reef seems suddenly to spring up before us, so steep is its slope.

The pleasure of the sight of a new and beautiful world of shapes and colours, mimicking yet utterly unlike those of life on land, is for us enhanced by the vigour of its life and growth, in happy contrast to the desert shore.

On the edge of the shoal Porites and other solid forms appear as great rocky buttresses among the lighter plant-like growths, or, a little way from it may rise from the depths as an isolated pillar. In many places in the Red Sea such coral pinnacles abound in comparatively deep water, a horror of unexpected danger to the sailor.

There is nothing more fascinating than the edge of a reef in the open sea, where numbers of forms and their delightful groupings can be seen in succession, one below another, till they become hazy and gradually lost in the blue depths, sixty to ninety feet below us. There are precipices clothed with a thick bush of spreading coral, some seeking the light by reaching out horizontally, others by growing upwards tree fashion, what appear to be bare rocks turning out to be massive colonies, as much alive as the more plant-like forms, caves, dark in contrast to the bright corals that surround their mouths, and the white shell-sand with which they are floored.

The general colour of living corals is very various, the snow white or creamy skeletons seen in museums being covered by a tinted film of polyps. The majority of species are some shade of brown, from deep chocolate to the golden colour of some seaweed covered boulders on home shores, but among these bright tints are abundant. The brown branches of Madrepora are generally tipped with light violet, pink or white, as though each ended in a flower, while other branched corals are a brilliant scarlet or bright green all over. Another forms a series of large thin sheets, spreading horizontally one above another, and all of a brilliant yellow! In these the flesh is inconspicuous, appearing as a mere colouring of the stony branches, but in others the polyps are as conspicuous as “sea-anemones,” with typical flower-like discs, a row of tentacles surrounding the mouth, or the tentacles may be so long that nothing else is visible. One of these, Galaxea, is very beautiful, shades of bright or dark green mingling with a greater or less proportion of brown, so that the rounded knolls of coral may resemble hillocks of grass, or of brown seaweed. Another large coral is almost devoid of tentacles altogether, but the polyps are large and the stone is covered as it were with green brown velvet, laid down in soft folds.

Of the inhabitants of these gardens and grottoes there is no space to speak. Anemones of all sizes and colours abound, and flower-like animals, the most beautiful of which are the sensitive sea-worms, add colour even to the corals. The gorgeous fish that lazily pass in and out, as though flaunting their beauty they could be careless of danger, have been described by every traveller.

The association between certain smaller fish, crabs and other higher animals with corals is remarkable. One sees for instance a branched coral with a shoal of tiny green fish hovering near, or in another case the fish are banded vertically black and white. Drop a pebble among them and they instantly disappear among the branches, and if the coral is taken out of the water the fish still cling to their refuge, and most of them are captured with it. These are but two examples of a whole world of life found only among corals.

Seeing that all corals are derivable from the sea-anemone (some form of which must have been the original ancestor of the whole family), and that the sea-anemone has been proved to be very distinctly an animal, I trust that the animal nature of the corals is now too firmly fixed in the reader’s mind to be shaken by their vegetable fixity, vegetative growth and form, or even by the fact that I am about to explain, viz. that the majority of corals do not obtain their nourishment by the capture of prey, but by the decomposition of the carbonic acid gas contained in the sea-water, a method of feeding which is the most distinctive feature of plant-life as opposed to animal. To recapitulate the well-known and fundamental fact of the life of this world, the plants are characterised by their taking up carbonic acid gas which, by the power of sunlight upon their green matter, they split up in some way so as to form starch from the carbon with water, while the oxygen is liberated back into the air. The animals, on the other hand, eat the food ready prepared for them by the plants, which is consumed in their bodies, and burned, as it were, back to carbonic acid, which land-animals get rid of in breathing. So there is a balance, the oxygen necessary to animal life being freed by the plants from the carbonic acid given by the animals, which carbonic acid is the necessary food-stuff of the plants.

The process in the sea is exactly similar, only that the gases concerned are dissolved in the water and rarely separate and become visible as bubbles. Fishes give off carbonic acid gas, dissolved in the sea-water, from their gills, and this is broken up by the seaweeds which liberate the oxygen from which the fishes and all animals re-form carbonic acid gas.