310 MISCELLANEOUS OBJECTIONS TO THE [Chap. TLT. 



with inheritance will have aided in an important manner 

 in their co-ordination. "With the many insects which 

 imitate various objects, there is no improbability in the 

 belief that an accidental resemblance to some common 

 object was in each case the foundation for the work of 

 natural selection, since perfected through the occasional 

 preservation of slight variations which made the resem- 

 blance at all closer ; and this will have been carried on 

 as long as the insect continued to vary, and as long as a 

 more and more perfect resemblance led to its escape from 

 sharp-sighted enemies. In certain species of whales 

 there is a tendency to the formation of irregular little 

 points of horn on the palate ; and it seems to be quite 

 within the scope of natural selection to preserve all 

 favourable variations, until the points were converted 

 first into lamellated knobs or teeth, like those on the 

 beak of a goose, — then into short lamellae, like those of 

 the domestic ducks, — and then into lamellae, as perfect 

 as those of the shoveller-duck, — and finally into the 

 gigantic plates of baleen, as in the mouth of the Green- 

 land whale. In the family of the ducks, the lamellae are 

 first used as teeth, then partly as teeth and partly as a 

 sifting apparatus, and at last almost exclusively for this 

 latter purpose. 



With such structures as the above lamellae of horn or 

 whalebone, habit or use can have done little or nothing, 



far as we can judge, towards their development. On 

 the other hand, the transportal of the lower eye of a 

 flat-fish to the upper side of the head, and the formation 

 of a prehensile tail, may be attributed almost wholly to 

 continued use, together with inheritance. With respect 

 to the mammae of the higher animals, the most probable 

 conjecture is that primordially the cutaneous glands 



