PARTHENOGENESIS AND ITS SEQUEL 309 



panied by, and largely moulded by, common instincts 

 and behavioiar, and this interpretation is only to be 

 reached by a study of the phenomena in their simplest 

 form among the lower grades of animal life. Colour and 

 the various sexual differences in form have been allowed 

 to dominate this investigation of the problem of sex, and 

 have diverted attention from more profitable and fruitful 

 channels. 



The lower we descend in the scale of animal life the 

 less convincing becomes the argument that the colour, 

 ornament or armature of the males is the result of sexual 

 selection in the older, Darwinian sense. The argument 

 of Geddes and Thomson and others that the males are 

 more " katabolic," the females more " anabolic," seems 

 no less unsatisfactory, for in many cases the female is 

 just as highly ornamented as the male, and in others 

 she is considerably large. Further, in their less specialized 

 species the sexes are almost or quite indistinguishable 

 externally, and are sombrely clad, just as at the opposite 

 extreme we find them equally ornamented and equally 

 active. 



We shall be nearer the truth if we regard these 

 secondary sexual characters as expression points of 

 germinal variations. Though we seem hopelessly ignorant 

 as to the inciting cause of the variations, at least we 

 seem to be able to lay a finger on the agents by which 

 they are effected. And these are the hormones of the 

 primary and secondary sexual glands, whose functions 

 affect more than the merely sexual side of the organism. 

 They profoundly affect the coloration of animals, giving 

 rise on the one hand to purely ornamental " secondary 

 sexual characters," and on the other to changes of color- 

 ation which achieve the ends of protective resemblance 



