288 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1923 



animals are all contemporaneous. The paleontologist, however, is 

 dealing with true genetic sequences, exact or approximate ; with the 

 evolution of species and genera of animals, not merely with illustra- 

 tions of how certain structures may have evolved. The time relations 

 of his specimens must be known exactly and carefully considered. 

 This has been always to the forefront in invertebrate paleontology. 

 Much of the early research in vertebrate paleontology, however, was 

 by men who were comparative anatomists rather than geologists, and 

 the fragmentary material with which they had to deal made a 

 thorough practical acquaintance with comparative osteology the first 

 essential to its correct identification and study. It is no less import- 

 ant to-day on account of the complex structure of the vertebrate 

 skeleton; but an inevitable consequence is a certain tendency to take 

 the anatomist's viewpoint and study too much the evolution of struc- 

 tures and not enough the actual sequence in time of the animals them- 

 selves. The corrective of this tendency is a closer union with the 

 geologists, and in the founding of our society it was hoped and ex- 

 pected that this would result. So far as I can see, the course of 

 American paleontology in the past two decades has demonstrated 

 the wisdom of this action. The exact records of specimens and more 

 careful stratigraphic studies have enabled us to define horizons and 

 differentiate faunas in much more precise and correct detail; and, 

 with the far larger collections and more complete specimens, the 

 records are adequate to trace in many cases the evolution of species 

 and not merely of structures. The earlier writers on evolution did 

 not attempt this. Gaudry and Haeckel, Rutimeyer and Kowalewsky, 

 Huxley, and Cope demonstrated from the paleontologic record the 

 evolution of structure. Deperet and Schlosser, Osborn and Scott, 

 and many others have perceived and pointed out this weakness in 

 our evidence and have attempted to trace the true phyla. But it is 

 only recently that the evidence has been adequate to place such at- 

 tempts on a really sound and permanent basis, and indeed most of 

 our work in this line is still tentative and provisional. Neverthe- 

 less, we may expect to see these beginnings extended year by year, 

 and the old structural phylogenies elaborated by the previous gen- 

 eration, and scoffed at with some justice by critics as a vast " schwin- 

 delbau," replaced by the veritable records of the phyletic history of 

 races of animals. In so far as this is accomplished, Professor Mor- 

 gan's strictures on paleontological evolution, 51 which are aimed 

 really at the old methods, not at our modern standards, will be no 

 longer justified. Paleontologists, with the facts before them as to 

 what actually did take place in the evolution of a race of animals, 

 may claim the right to reason and draw conclusions from these data 

 as to the methods and causes of the transmutation of species. 



51 See footnote 50, 



