XXXIV LIFE AND WORKS OF COPE. 



have been the despair of the public printer, owing to the 

 constant additions made while in press. It extends from 

 the Puerco to a portion of the Lower Miocene fauna. Be- 

 sides the full description and illustration of the great hoofed 

 orders above alluded to, it contains the full exposition of 

 the characteristic forms of (Jreodonta, an order of primitive 

 carnivora, which, as we have seen, he separated from the 

 Marsupialia in 1875, and in which he placed six families of 

 mammals from different parts of the world. 



Before leaving the mammals it is fitting to speak of his 

 work upon " kinetogenesis," or the mechanical origin of the 

 hard parts of the body, especially of the teeth, vertebrae, and 

 limbs. An invaluable paper by his friend and later col- 

 league, Ryder, put him upon this line of investigation, the 

 results of which he published in a long series of papers, cul- 

 minating in his memoir upon the " Origin of the Hard Parts 

 of the Mammalia," and in his collections of essays in the 

 "Origin of the Fittest" and "Primary Factors of Organic 

 Evolution." One of his chief motives in these researches 

 was the demonstration, which he believed they afforded, 

 of the hereditary transmission of the effects of individual 

 efforts, use, and disuse ; even if this motive is subsequently 

 shown to be an illusive one, by our future knowledge of the 

 real nature of evolution, these investigations lose little, if 

 any, of their intrinsic value. First, as in all his work, he 

 brings together an immense array of valuable facts and 

 observations ; second, he extends the principle of the inde- 

 pendent origin of similar structures ; third, he in most cases, 

 successfully establishes the actual mechanical adaptive or 

 teleological relations of the parts described ; fourth, he 

 traces the course of phylogenic modification in a number of 

 important organs and thus establishes certain obscure 

 homologies, notably those in the teeth of Amblypoda,, Cory- 

 2)hodon and Uintatheriiim. 



As to his scientific character apart from his genius, which 



