8 THE AGE OF MAMMALS 



history of mammalian paleontology, including the labors of those men- 

 tioned above as well as of the great Swiss palaeontologist, Ludwig Ruti- 

 meyer (1825-1895). It was under the inspiration of the " Odontographie " '■ 

 of Riitimeyer that Kowalevsky completed and published in 1873 his four 

 remarkable memoirs upon the hoofed mammals. He wrote these four 

 hundred and fifty quarto pages in three languages not his own, in French 

 upon Anch'itherium and the ancestors of the horses, in English on the 

 Hyopotamidae, in German upon other types of even-toed mammals, namely, 

 Gelocus, Anthracotherium, and Entelodon,^ including the first attempt at 

 an arrangement of these great groups of mammals on the basis of the 

 descent theory. It is to the everlasting renown of the veteran Riitimeyer 

 and of Kowalevsky, unfortunately so soon deceased, that while their main 

 inductions as to the descent of the mammals and even as to the structure 

 of certain parts of mammals, such as the teeth, have suffered by the fullness 

 of American discoveries, their methods of thought and still more their 

 thorough methods of research have not been displaced. Kowalevsky's 

 theory of the pedigree of the horses, like that of Huxley, was not the right 

 one; Riitimeyer believed that the grinding teeth of hoofed mammals sprang 

 from lophodont or crested forms, which also has been disproved. It is, 

 nevertheless, the right system of thought which is most essential to prog- 

 ress; and better in the end wrong results which have been reached by 

 right methods than right results reached haphazard by vicious methods. 

 If a student to-day asks, " how shall I study palaeontology," we can do no 

 better than to direct him to the Versuch einer Natiirlichen Classification 

 der Fossilen Hufthiere of Kowalevsky, out of date in some of its facts, 

 thoroughly modern in its method of approach to ancient nature. This 

 work is a model union of the detailed study of form and function with 

 theory and the working hypothesis. It regards the fossil not as a petri- 

 fied skeleton, but as having belonged to a moving and feeding animal; 

 every joint and facet has a meaning, each cusp a certain significance. Ris- 

 ing to the philosophy of the matter, it brings the mechanical perfection 

 and adaptiveness of different types into relation with environment, with 

 changes of herbage, with the introduction of grasses. In this survey of 

 competition it speculates upon the causes of the rise, spread, and extinc- 

 tion of each animal group. In other words the fossil quadrupeds are 

 treated biologically — so far as possible in the obscurity of the past. From 

 such models and from our own experience we learn to feel free to abandon 

 outworn traditions in the use of the tools of science, such as mere methods 

 of description and classification, and to conserve a reasonable priority in 

 nomenclature only. 



' Riitimeyer, L., Beitrag zur Kenntniss der fossilen Pferde und zu einer vergleichenden 

 Odontographie der Hufthiere im Allgemeinen. Verh. naturf. Ges. Basel, Vol. Ill, no. 4, 1863. 



- Readers desiring to ascertain the zoological relations of these and other mammals 

 mentioned in the text should consult the index and appendix. 



