xii PREFACE. 



articulations of the tarsus. These explanations, so far as based on paleonto- 

 logical grounds, were new at the time. 



XVI. The Effect of Impact and Steains on the Feet of Mammalia. 

 From " The American Naturalist," July, 1881. 



The origin of the structures of all the articulations of the limbs of all the 

 Mammalia are explained as the effects of impacts and strains. The demon- 

 stration is based largely on paleontological evidence, and is new. 



XIX. On Aechaesthetism. From " The American Naturalist," June, 

 1882. 



This doctrine is discussed and illustrated on the basis laid down in the 

 essay " Consciousness in Evolution," and a classification of theories of crea- 

 tion is presented. 



IX. The Developmental Significance of Human Physiognomy. From 

 "The American Naturalist," June, 1883. 



In this paper suggestions presented in Art. I Y, entitled " The Hypothe- 

 sis of Evolution, Physical and Metaphysical," are developed, and the physical 

 significance of the form-characters of men in general are considered. Noth- 

 ing except reference to a few leading points of the subject had been pub- 

 lished prior to this paper, so far as the author has been able to discover. In 

 connection with a paper on the " Evolutionary Significance of Human Char- 

 acter," a foundation was laid for a scientific physiognomy. 



X. The Evidence for Evolution in the History of the Extinct 

 Mammalia. A lecture delivered before the American Association for the 

 Advancement of Science, at Minneapolis, August, 1883. 



In this paper are collected the evidences of descent displayed by the 

 Mammalia (and in one instance by the Batrachia), as derived from the pale- 

 ontological researches of the author. These had been in some points fore- 

 shadowed in the author's memoir on the homologies and origin of the struct- 

 ure of the molar teeth in the Mammalia Educabilia in 1874, which were 

 here shown to have been realized by subsequent discovery, and a number 

 of other evidences added. Restatements of the laws of kinetogenesis, and 

 of the origin of morals, were made. 



XVII. The Evolutionary Significance of Human Character. From 

 the " American Naturalist," September, 1883. 



The characters of the adult mind are compared with those of the child, 

 and with those of the lower animals, and the direction of their evolution 

 pointed out. Most of the propositions contained in this paper were new at 

 the time of its publication. 



XIII. The Tritubercular Type of Molar Teeth in the Mammalia. 

 From the proceedings of the American Philosophical Society, 1883, page 

 324;* published in advance in the "Paleontological Bulletin," No. 37, 

 January 2, 1884. 



The origin of the ungulate molar tooth had already been traced to a 

 quadritubercular type in paper No. VII (March and January, 1874). The 



* Not published until 1884. 



