[40]Except certain rare forms obtainable only from very deep water in the Atlantic.
[41]More correctly by decomposition of calcium sulphate, thus,
CaSO₄ + H₂CO₃ = CaCO₃ + H₂SO₄,
since the sulphate forms 3·6% while the carbonate only forms 0·2% of the salts dissolved in sea-water.
[42]Similar masses are common in the Red Sea, but I do not know of a case quite so striking as this.
[43]The apes include a wide variety of type, e.g. the baboon is on the whole lower than the ordinary monkey, which is lower than the big man-like apes, chimpanzee, orang-outang and gorilla. The lemurs link lower monkeys and ordinary quadrupeds. See Huxley’s essay “On the relations of man to the lower animals,” 1863.
[44]Avoid the conception of descent as the highest fish giving rise to the lowest amphibian, the highest amphibian giving birth to the lowest reptile, and so on. The fishes did not cease their evolution when the amphibia appeared, and ancestral types must have been generalised, and so, in one sense, lowly forms.
[45]More accurately gypsum, CaSO₄, which is decomposed to form limestone CaCO₃ as noted bottom of [page 89] above.
[46]To obtain a specimen of coral of this beautiful snow-white colour it is necessary to remove the flesh from any living colony, which is usually coloured brown or yellow, by rotting the same for a week in sea-water in a bucket. Cover the bucket to keep out dust, and change the water a few times to reduce the smell. The last traces of decayed flesh are removed by dashing buckets of water on to the coral. Rinse in fresh water. Or the specimens may be dried thoroughly, rotted in water after return to Europe, and finally bleached with hydrogen peroxide.
[47]See for instance, among other literature by the same author, “The Fauna and Geography of the Maldives and Laccadives,” Cambridge University Press, and “The Percy Sladen Trust Expedition to the Indian Ocean,” by J. Stanley Gardiner, M.A., F.R.S., etc., Transactions Linnean Soc. Zoology, Vol. XII., pp. 35, 51, and illustrations on Plate IX, and on pages 128 and 135.