. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. COLORS AND MARKINGS OF ANIMALS 441 thus shingled above and below (fig. 228) by thousands of tiny scales which produce all its colors and markings. These colors are made in two ways; either the scales are actually brownish or reddish or yellowish or black themselves be- cause they contain pigment granules inside, or else they reflect white light in such a way that it is broken up, as by a prism, into colors, only some of which reach our eyes. The metallic and iridescent kinds, the greens, blues,
. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. COLORS AND MARKINGS OF ANIMALS 441 thus shingled above and below (fig. 228) by thousands of tiny scales which produce all its colors and markings. These colors are made in two ways; either the scales are actually brownish or reddish or yellowish or black themselves be- cause they contain pigment granules inside, or else they reflect white light in such a way that it is broken up, as by a prism, into colors, only some of which reach our eyes. The metallic and iridescent kinds, the greens, blues, coppers, purples, etc., all of which change somewhat as we change the position of our eyes, are produced in the second way. The duller and the fixed colors, such as the reds, yellows, browns, etc., are produced by scales con- taining pigments of the same shade. Colors of other animals. —^The colors of other ani- mals are also produced in one or both of these two ways; that is, either by col- ored pigment, or by reflec- tions from structures which act as the prism does. Only a few other animals have scales, and almost no others have scales just like those of the butterfly, but they have other kinds of structures on the outside of the skin, such as feathers or hairs, which contain pigment, or break up white light into colors. Observe the coloring on a blackbird; note the fine iri- descent blue and purple or bronze-green reflections. These are made by the feathers reflecting broken-up white light. Such iridescent colors produced by structure, and hence called structural colors, are especially pronounced and. Fig. 227. Bit of rubbed wing of a butterfly, Grapta sp., greatly mag- nified, to show the rows of scale insertion pits op both upper and lower sides of the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original
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