REPORT OF ACTING ASSISTANT SECRETARY. 37 



the Horizons of Extinct N'ertebrata of Europe and North America" 

 (1870); '-'The Origin of the Fittest" (1887), and "The Primary Factors 

 of Organic I^vohition." 



A complete bibliography of his writings is in preparation under the 

 auspices of the National Museum, and an elaborate monograph of the 

 Ilei)tilia of NTorth America, which he had completed shortly before his 

 death, will be published by the Museum. 



Professor Cope was president of the American Association for the 

 Advancement of Science, editor of the American Naturalist, and a 

 member of the faculty of the University of Pennsylvania. 



