CONTENTS. 



to sea-urchins ; as to certain processes of metamorphosis ; as to the 

 mammary gland ; as to certain ape characters ; as to the rattlesnake 

 and cobra ; as to the process of formation of the eye and ear ; as to 

 the fully developed condition of the eye and ear ; as to the voice ; as 

 to shell-fish ; as to orchids ; as to ants. The necessity for the simulta- 

 neous modification of many individuals. Summary and conclusion. 



Page 26 



CHAPTEE III. 



THE CO-EXISTENCE OF CLOSELY SIMILAR STRUCTURES OF 

 DIVERSE ORIGIN. 



Chances against concordant variations Examples of discordant ones. 

 Concordant variations not unlikely on a non-Darwinian evolutionary 

 hypothesis. Placental and implacental mammals. Birds and reptiles. 

 Independent origins of similar sense organs. The ear. The eye. 

 Other coincidences. Causes besides "Natural Selection" produce con- 

 cordant variations, in certain geographical regions. Causes besides 

 "Natural Selection" produce concordant variations, in certain zoological 

 and botanical groups. There are homologous parts not genetically 

 related. Harmony in respect of the organic and inorganic worlds. 

 Summary and conclusion Page 71 



CHAPTER IV. 

 MINUTE AND GRADUAL MODIFICATIONS. 



There are difficulties as to minute modifications, even if not fortuitous. 



Examples of sudden and considerable modifications of different kinds. 



Professor Owen's view. Mr. Wallace. Professor Huxley. Objections 

 to sudden changes. Labyrinthodont. Potto. Cetacea. As to origin 

 of bird's wing. Tendrils of climbing plants. Animals once supposed 

 to be connecting links. Early specialization of structure. -Macrau- 

 chenia. Glyptodon. Sabre-toothed tiger. Conclusion . Page 109 



