Page:The Zoologist, 4th series, vol 3 (1899).djvu/477

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MIMICRY.
447

adduced. But an illustration was alone intended. In the present category the records are, however, much more numerous, and considerably more familiar, to all who take an interest in the subject. We are now in the realm of suggestion, and among naturalists who incline to theory there is often much faith. As Lecky has observed, referring to another subject, "Their measure of probability ultimately determines the details of their creed."[1]

Recently a new suggestion has been made as to "Nocturnal Protective Colouration in Mammalia, Birds, Fishes, Insects, &c, as developed by Natural Selection." The author, Mr. A.E. Verrill, truly remarks that much has been written in respect to the imitative and protective colours of these groups, as seen by daylight, and the bearing of these facts on natural selection is well known. Very little attention has been paid to their colours, as seen by twilight, moonlight, and starlight. Yet it is evident that protection is more needed during the night than in the daytime by a very large number of species. This is the case with those that move about in search of their food at night, as is the habit of numerous forms of small mammals, such as rodents (Rats, Mice, Arvicolæ, &c), insectivores (Moles, Shrews, &c), many herbivores, various marsupials, and members of other orders. Many carnivorous species, which seek their prey at night, will also find advantages in such protective colours, for thus they will more easily escape the notice of their prey. Hence many nocturnal carnivores are black or nearly so, as the Mink, Fishes, some Bears, &c. The same principles will apply to birds, reptiles, fishes, and to insects, both in their larval and adult states, for many members of all these groups are very active at night, and hide away in holes or beneath dense herbage by day.... Many nocturnal insects that live on the ground are black or dark brown, which are colours that are protective only

  1. Charles Kingsley complained:—"Weak and wayward, staggering and slow, are the steps of our fallen race (rapid and triumphant enough in that broad road of theories which leads to intellectual destruction)." ('Glaucus,' p. 30.) Perhaps Kingsley would have approved of an old and summary method, as described by Gibbon:—"A Locrian who proposed any new law stood forth in the assembly of the people with a cord round his neck, and, if the law was rejected, the innovator was instantly strangled." ('Decline and Fall.') Dr. A.B. Meyer has recently remarked:—"It must be admitted that it is not very difficult to invent pleasing and clever hypotheses, specially convincing to the laity." ('Distribution of the Negritos,' pp. 81–2.)