II.] INCIPIENT STRUCTURES. 61 



How, then, could either the minute incipient stages, or 

 the final perfecting touches of this admirable structure, 

 have been brought about by vague, aimless, and indelinite 

 variations in all conceivable directions of an organ suited 

 to enable the rudest savage to minister to his necessities, 

 but no more ? 



^Ir. Wallace^ makes an analo2fOus remark with regard to 

 the organ of voice in man — the human larynx. He says 

 of singing : " The habits of savages give no indication of 

 how this faculty could have l)een developed by Xatural 

 Selection, because it is never required or used by them. 

 The sinmna' of sava<:^es is a more or less monotonous 

 howling, and the females seldom sing at all. Savages cer- 

 tainly never choose their wives for fine voices, but for rude 

 health, and strength, and physical beauty. Sexual selection 

 coukl not therefore have developed this wonderful power, 

 which only comes into play among civilized people." 



lieverting once more to beauty of form and colour, there 

 is a manifestation of it for which no one will pretend that 

 sexual selection can possibly account. The instance re- 

 ferred to is that presented by bivalve shell-fish.- Here we 

 meet with brilliant tints and eleiJant forms and markings 

 of no direct use to their possessors'^ in the struggle for life, 

 and of no indirect utility as regards sexual selection, for 

 fertilization takes place by the mefe action of currents of 

 water, and the least beautiful individual has fully as good 



1 '* Natural Selection," p. 350. 



2 Bivalve sliell-lisli are creatures belonging to the oyster, scallop, and 

 coclvle group, i.e. to the class Laniellibranchiata. 



3 The atteni})t has been made to explain these facts as owing to 

 "manner «nd symmetry of growth, and to colour being incidental on the 

 chemical nature of the constituents of the shell." 13ut surely beauty 

 depends on some such matters in cell cases ! 



