PREFACE. xiii 



present paper shows that this type in the upper jaw is a derivative of a tri- 

 tubercular type, while that of the lower jaw is a derivative of a quinquetu- 

 bercular type, or a tritubercular type With a heel, which may support two 

 additional tubercles. The tritubercular type was again traced to the sim- 

 ple cone. This generalization was new at the time of publication. 



XX. Catagenesis. Vice-presidential address delivered before the bio- 

 logical seciion of the American Association for the Advancement of Sci- 

 ence, Philadelphia, September 4, 1884. 



The hypothesis of catagenesis which is put forth in this paper teaches 

 that primitive energy was and is conscious, and that all unconscious forms 

 of energy, whether " vital " or non-vital, have been derived from it by a 

 process of retrograde metamorphosis. The first stage of this retrogression 

 is the loss of consciousness, or cryptopnoy. Evidence for this kind of meta- 

 morphosis is derived from every-day experience, and from the designed 

 character of automatic acts. That a form of energy is conscious is inferred 

 from the nature of designed conscious acts of animals. The author had not 

 met with any scientific statement of this theory prior to the preparation of 

 this lecture. 



XI. The Evoltition of the Veetkbeata, Peogeesstve and Reteo- 

 GEESsivE. From the " American Naturalist," February, March, and April, 

 1885. 



This paper sets forth the results of paleontological investigation of the 

 Vertebrata, in a series of phylogenies. These are, first, the phylogeny 

 of the classes ; then the special phylogenies of their contents or of the 

 orders. Here are introduced the newly-discovered relations of the Anti- 

 archa and the Ichthyotomi to the fish-like vertebrates, and of the thero- 

 morphous reptiles to the Mammalia. Also, the ancestral relation of the 

 Theromorpha to most other reptiles, and of the Condylarthra to the placental 

 Mammalia, and to man. Many of the other results set forth in this essay 

 are derived from the paleontological researches of the author. Some of 

 them, especially the lemurine (condylarthrous) ancestry of the placental 

 Mammalia, had been anticipated on theoretical grounds by Haeckel in his 

 " History of Creation " (" Schopfungsgeschichte "). Haeckel was very 

 general in his proposition, and did not anticipate the details of the demon- 

 stration. My investigations enabled me to produce these, which bring out 

 in a striking manner the sagacity of Prof. Haeckel. I consider further the 

 question of degeneracy, and the significance of the phylogeny with refer- 

 ence to this subject is pointed out. 



In conclusion, it may be said that the principal object which the author 

 set before him, in the studies here recorded, has been tbe discovery of 

 the laws of variation, or of the "Origin of the Fittest." These essays 

 express the light which he has been able to obtain on this difiicult question 

 up to the present time. The results could be better and more briefly pre- 

 sented in a systematic form, but the author reserves this for a future occa- 

 sion. 



