Page:The Zoologist, 4th series, vol 3 (1899).djvu/480

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THE ZOOLOGIST.

suggestion: Certain tan-spots occur over the eyes of semi-domesticated Dogs. They do not exist in wild animals allied to the Dog, or in the modern breeds of fully-domesticated Dogs. The spots are most conspicuous when the eyes are closed, appearing then like opened eyes. They "may have been protective to the animals during sleep, causing them to look as if wide awake." This speculation has been supported by no less an authority than Mr. A.R. Wallace.[1] Waterton, in describing the South American Sloth, writes: "His fur has so much the hue of the moss which grows on the branches of the trees that it is very difficult to make him out when he is at rest."[2] The Philippine Koel, or Phow (Eudynamis mindanensis), one of the Cuckoos, is an example of a bird in which the young does not follow the general rule of having the plumage of the female, or one distinct from that of both parents. Mr. Whitehead accounts for this by the fact of the Phow laying its eggs in the nest of the Yellow-wattled Myna. "The young Cuckoo, being black, does not differ from the young Myna, and so the deception is carried on until the young bird can take care of itself. If the young followed the general rule, and resembled their mother in being of a brown colour, the Mynas might not feed them."[3] Of the Matamata Tortoise (Chelys fimbriata), a South American species, it has been observed:—"When in its native element the warty appendages on the neck float in the water like some vegetable growth, while the rugged and bossed shell strongly resembles a stone; it is thus probable that the whole appearance of the creature is advantageous either in deluding its enemies or in attracting to it the animals on which it feeds, the latter being the most likely hypothesis. Although it appears that the Matamata will occasionally eat vegetable substances, its chief food consists

  1. 'Nature,' vol. li. p. 533.
  2. 'Wanderings,' Wood's edit. p. 219.—We may here refer to "the law which underlies Protective Coloration" as propounded by Mr. Abbott H. Thayer, the law of gradation in the colouring of animals, which "is responsible for most of the phenomena of protective coloration except those properly called mimicry.... Mimicry makes an animal appear to be some other thing, whereas this newly-discovered law makes him cease to appear at all." Thus "animals are painted by nature darkest on those parts which tend to be most lighted by the sky's light, and vice versâ." (Cf. 'The Auk,' vol. xiii. 1896; and reprint 'Ann. Rept. Smith. Instit.' for 1897, p. 477).
  3. Cf. 'Royal Nat. Hist.' vol. iv. p. 7.