LIFE AND WORKS OF COPE. XXI 



the more exhaustive monographic treatment of the rich 

 amphibian and reptilian fauna of this period, exclusively 

 collected and described by him, would constitute a volume 

 of the Hayden Survey memoirs and give him an oppor- 

 tunity of rounding up his prolonged studies. This volume 

 was never completed. 



In the meantime his investigations upon the living 

 Batrachia extended to Central and South American species, 

 as well as to include his very original observations upon 

 the laws of geographical distribution of the Amphibia, 

 which were published by the Smithsonian Institution. In 

 1875 he prepared a " Check List of the North American Ba- 

 trachia and Reptilia " for the U. S. "National Museum ; this 

 was followed by an essay " On the Zoological Position of 

 Texas " (1880). Soon afterwards, at the request of Spencer 

 F. Baird, Secretary of the Smithsonian Institution, he 

 began the preparation of a general work upon the Batra- 

 chia ; this was facilitated by a manuscript prepared for a 

 work of the same character both by Baird and Girard, but 

 was not completed until 1889. As a volume of 523 pages 

 and numerous plates this work,* while showing many 

 signs of haste and subject to considerable changes in the 

 larger systematic divisions, fortunately remains as a monu- 

 ment of the immense range of knowledge and observation 

 of its author upon the structure and habits of the living 

 representatives of this group. It must always be a matter 

 of regret that he could not have published his final views 

 upon the extinct forms. One of his most important gen- 

 eralizations from the latter, contained in a short memoir, 

 " The Intercentrum of the Terrestrial Vertebrata " (1881), is 

 that the vertebrae of living amphibia are composed of inter- 

 centra and are, therefore, not homologous with the true 

 centra (pleurocentra) of reptiles, birds, and mammals. 



* " The Batrachia of North America." Bull. No. 34, U. S. Nat. Museum. 



