252 THE GENESIS OF SPECIES. [Chap. 



those last touches of mimetic perfection, \vliere an insect 

 not only mimics a leaf, but one worm-eaten and attacked 

 by fungi. 



Also, that structures like the hood of the col.>ra and 

 the rattle of the rattlesnake seem to require another 

 explanation. 



Again, it lias been contended that instances of colour, as 

 in some apes ; of beauty, as in some shell-fish ; and of 

 utility, as in many orchids, are examples of conditions 

 which are quite beyond the power of Natural Selection to 

 originate and develop. 



Next, the peculiar mode of origin of the eye (by the 

 simultaneous and concurrent modification of distinct parts), 

 with the wonderful refinement of the human ear and voice^ 

 have been insisted on ; as also, that the importance of all 

 these facts is intensified through the necessity (admitted by 

 Mr. Darwin) that many individuals should be similarly 

 and simultaneously modified in order that slightly favour- 

 able variations may hold their own in the struggle for life, 

 against the overwhelming force and influence of mere 

 number. 



Again, we have considered, in Chapter III., the great 

 improbability that from minute variations in all direc- 

 tions, alone and unaided, (save by the survival of the fit- 

 test), closely similar structures should independently arise ; 

 though, on a non-Darwinian evolutionary hypothesis, their 

 development might be expected a priori. We have seen, 

 however, that there are many instances of wonderfully 

 close similarity which are not due to genetic affinity ; the 

 most notable instance, perhaps, being that brought forward 

 by ^Ir. Murphy, namely, the appearance of the same 

 eye-structure in the vertebrate and molluscous sub- 



