396 PACKARD— ORIGIN OF MARKINGS OF ORGANISMS. [Dec. 2, 



Miiller and their followers, has a precarious basis. There are, to be 

 sure, interesting coincidences, but a coincidence is not a vera causa. 

 Natural selection as such is inadequate as an originating cause, 

 though it operates as a preservative agent. The markings appar- 

 ently did not originate in single variations, liable to be swamped by- 

 crossing, but whole masses of individuals, all those inhabiting a 

 given area with its peculiar features, have been affected alike. The 

 causes were not primarily biological and limited, dependent on 

 sporadic and individual variations, but physical and widespread, 

 occurring in different regions. 



It will also be seen that the Bates-Mliller hypotheses are seriously 

 undermined by the fact that the wings of insects were, as early as 

 the Carboniferous period, striped or barred and spotted, long before 

 birds ever appeared. 



Mr. Abbott H. Thayer, with the keen powers of observation of the 

 artist as regards the effects of light and shade, hits upon the right 

 explanation when he claims that protective coloration makes the 

 animal "cease to appear to exist at all," and that ''animals are 

 painted by nature darkest on those parts which tend to be most 

 lighted by the sky's light," and vice versa. He likewise points out 

 that what naturalists call conspicuous colors, i.e., strong arbitrary 

 patterns of color, "tend to conceal the wearer by destroying its 

 apparent continuity of surface. Thus the mallard's dark green 

 head tends to detach itself from its body and to join the dark green 

 of the shady sedge, or the ruby of the humming bird to desert it and 

 to appear to belong to the flower it searches." His experiments 

 capitally illustrate and confirm his views. 



Steinach's earlier experiments seem to conclusively prove that 

 light and shade acting on the integument of the living frog, or its 

 dead and dry skin, cause light and dark markings. 



Pocock has clearly shown that zebras and antelopes are banded, 

 or not, in accordance with the nature of their habitat or environ- 

 ment, i.e., whether they are confined in their range to forest regions 

 or to the bush or to open plains. 



It thus appears to be fairly w^ell established that the markings of 

 the skin and scales or feathers and hair of animals are due to the 

 effect of the sun's light, or its absence, on the pigment in the in- 

 tegument, or its covering. 



The biological cause suggested by Bates and by Miiller, and so 

 strongly advocated and extended by their followers, now appears to 



