Luminosity is a character of many lowly animals, and it is the presence of minute creatures possessing this character which so often causes the spray dashed from the prow of an advancing ship to appear like a shower of sparks, while glowing bodies traverse the water beneath its surface. Many insects, such as fire-flies and glow-worms, are notoriously luminous. In the vegetable world, however, this character is very rarely present, being only so in certain fungi, some of which exhibit a wonderful luminosity. Humboldt relates that he found this to be especially splendid in mines.
As like phenomena of colour characterize certain groups of living creatures, so also like phenomena of colour may characterize certain geographical regions being common to creatures of very different kinds which inhabit such regions, as we shall hereafter see. The brightest of living things, the humming birds, have their true home in the equatorial region of America, to which continent they are exclusively confined. But it is in the equatorial region of the whole earth that we find the most brilliant birds of other kinds, the most brightly coloured reptiles and fishes, the largest and many of the loveliest butterflies, moths and beetles, the most beautiful orchids, the largest of all flowers and of all clusters of flowers.
But neither the temperate, nor even the Arctic nor Antarctic climes are denied the glory of bright tints in the long days of their brief, but sometimes fervid, summer. Indeed, the golden burst of gorse and glow of heather in our temperate zone have, in their way, an unequal charm; while every here and there Arctic lands and Alpine heights exhibit beauties of colour which are hardly elsewhere presented by the field of animated nature to the eye of man.
St. George Mivart.
FOOTNOTES:
[56] Contemporary Review for July, 1879, p. 678.
[57] Loc. cit., p. 704.
[58] Contemporary Review for July, 1879, p. 703.
[59] Ibid. for September, 1879, p. 27.
[60] Contemporary Review, September, 1879, pp. 33 and 43.