THE GENEALOGY OP THE VERTEBRATA AS 

 LEARNED FROM PALEONTOLOGY. 



AN ADDRESS DELIVERED BEFORE THE 



VASSAR BROTHERS INSTITUTE, 



January 27, 1885. 



BY PROF. EDWARD D. COPE. 



A great deal of light has been happily thrown on the 

 question of the phylogeny of the Vertebrata, by the re- 

 cent work done in North American paleontology. The 

 lines of descent of many of the minor groups have been 

 positively determined, and the phylogenetic connections 

 of most of the primary divisions or classes have been 

 made out. The result of these investigations has been to 

 prove that the evolution of the Vertebrata has proceeded 

 not only on lines of acceleration, but, to a much greater 

 extent than has been heretofore suspected, on lines of 

 retardation. 1 That is, that evolution has been not only 

 progressive, but at times retrogressive. This is entirely 

 in accord with the views derived by Dohrn from em- 

 bryology, 2 who, however, wrote only of the origin of the 

 Vertebrata as a whole and not of its divisions, excepting 

 only the Leptocardii and Marsipobranchii, that is, of the 

 sand lance and the lampreys and hags. The demonstra- 

 tion of such relations for the higher Vertebrata is now 

 done nearly for the first time. 3 



1 Sue Origin of Genera, E. D. Cope, Philadelphia, 1868, where these terms are introduced. 



■: See Der Ursprung der Wirbelthiere u. d. Princip des Functionwechsels, Leipsic, 1875. 



30n the Phylogeny of the Vertebrata, Cope, Amer. Naturalist, Dec., 1884. I here re- 

 mark that my researches have now, as I believe, disclosed the ancestry of the mammals, the 

 birds, the reptiles and the true fishes, or Teleostomi, including the special phylogenies of 

 the Batrachia and Reptilia, and some of the Mammalia. See the following references ; 

 American Naturalist, 1884, p. 1136 : Proceedings Academy Philadelphia, 1867, p. 234 ; Pro- 

 ceedings American Philosoph. Society, 18S4. p. 585 ; American Naturalist, 1884, p. 27 ; Pro- 

 ceedings American Association for the Advancement of Science, six., 1871, p. 233 ; Proceed- 

 ings American Philosophical Society, 1882, p. 447 : American Naturalist, 1884, pp. 261 and 

 1121 ; Report U. S. Geol. Survey W. of 100th Mer., G. M. Wheeler, 1877, iv., ii., p. 282. 

 Amer. Naturalist, Feb., March, and April, 1885. 



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