14 PREFACE 



missioner of Parks Mr. F. Alber placed the resources of the 

 Cleveland Zoological Park completely at my disposal. To all 

 these gentlemen I would gratefully acknowledge my indebted- 

 ness. Professor R. A. Budington of Oberlin and Mr. "W. H. 

 Cathcart of the Western Reserve Historical Society's Museum 

 have shown me many kindnesses. 



The great majority of the illustrations are photographs from 

 specimens in this laboratory but for some I am indebted to the 

 kindness of other writers. Figs. 57C and 80 are photographs 

 of specimens loaned to me by Professor Budington from the 

 museum of the Zoological Laboratory of Oberlin College. By 

 Dr. Matthew's courtesy Fig. 1 is reproduced from his work 

 Climate and Evolution. Fig. 2 is modified from Prof. V. But- 

 tel-Reepen's work Man and His Forerunners. Figs. 3, 4 and 86 

 are from Comparative Dental Anatomy by Drs. Thompson and 

 Dewey. Fig. 5 is from Tomes' well-known Dental Anatomy. 

 Dr. Gregory very kindly made a modification of his Fig. 2 

 Orders of Mammals for incorporation as Fig. 8 of this work and 

 also permitted me to copy Fig. 94 from his Studies on the Evolu- 

 tion of the Primates (Part I). Figs. 9, 10, 11 and 12B are taken 

 from Dr. R. Broom's writings (see Appendix). Owing to war 

 conditions it has been impossible unfortunately to communi- 

 cate directly with Dr. Broom in order to secure from him an 

 expressed willingness for the utilization of his figures. Yet I 

 feel sure this permission would readily have been granted had 

 it been possible to reach Dr. Broom himself. Fig. 12A is from 

 the late Professor H. G. Seeley's monograph on Diademodon 

 (Phil. Trans. Roy. Soc, 1894, vol. 185, p. 1029). 



Professor H. F. Osborn and the Macmillan Company have 

 kindly allowed me to reproduce Figs. 13 and 14 from Evolution 

 of Mammalian Molar Teeth. Figs. 15 and 16 are obtained 

 through the courtesy of E. S. Goodrich, Esq., and J. W. Gidley, 

 Esq., respectively. On account of the transportation diffi- 

 culties then affecting the United States the works (noted in the 

 Appendix) of these two gentlemen from which these figures were 



