Chap. XIV.] MOEPHOLOGY. 235 



subject ; namely, serial homologies, or the comparison 

 of the different parts or organs in the same individual, 

 and not of the same parts or organs in different 

 members of the same class. Most physiologists believe 

 that the bones of the skull are homologous — that is, 

 correspond in number and in relative connexion — with 

 the elemental parts of a certain number of vertebrae. 

 The anterior and posterior limbs in all the higher 

 vertebrate classes are plainly homologous. So it is 

 with the wonderfully complex jaws and legs of crus- 

 taceans. It is familiar to almost every one, that in 

 a flower the relative position of the sepals, petals, 

 stamens, and pistils, as well as their intimate structure, 

 are intelligible on the view that they consist of meta- 

 morphosed leaves, arranged in a spire. In monstrous 

 plants, we often get direct evidence of the possibility of 

 one organ being transformed into another ; and we can 

 actually see, during the early or embryonic stages of 

 development in flowers, as well as in crustaceans and 

 many other animals, that organs, which when mature 

 become extremely different are at first exactly alike. 



How inexplicable are the cases of serial homologies 

 on the ordinary view of creation ! Why should the 

 brain be enclosed in a box composed of such numerous 

 and such extraordinarily shaped pieces of bone, appa- 

 rently representing vertebras ? As Owen has remarked, 

 the benefit derived from the yielding of the separate 

 pieces in the act of parturition by mammals, will by 

 no means explain the same construction in the skulls 

 of birds and reptiles. Why should similar bones have 

 been created to form the wing and the leg of a bat, 

 used as they are for such totally different purposes, 

 namely flying and walking? Why should one crus- 

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