CONTENTS. 



the Eattlesnake 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 Simultaneous Modification 

 of Many Individuals. Summary and Conclusion . . . . p. 35 



CHAPTEE III. 



THE COEXISTENCE 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 Eeptiles. Independent Origins of Similar 

 Sense Organs. The Ear. The Eye. Other Coincidences. Causes besides Natural 

 Selection produce Concordant Variations in Certain Geographical Eegions. 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 . p. 76 



CHAPTEE 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. Prof. Owen's View. 

 Mr. "Wallace. Prof. 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. 

 Macrauchenia. Glyptodon. Sabre-toothed Tiger. Conclusion . . p. Ill 



CHAPTEE V. 



AS TO SPECIFIC STABILITY. 



What is meant by the Phrase " Specific Stability ; " such Stability to be expected a 

 priori, or else Considerable Changes at once. Eapidly-increasing DiflSculty of in- 

 tensifying Eace Characters ; Alleged Causes of this Phenomenon ; probably an In- 



