316 



PROCEEDINGS OF THE jSTATIONAL jVIUSEUM 



were temporary employees engaged to do special items of work. In 

 table 1 is given a complete list of these employees, with the dates of 

 their appointment and separation : 



Table 1. 



-Employees of the Division of Vertebrate Paleontology and their terms 

 of service 



In addition to those of the regular staff there have been several vol- 

 unteer collaboratoi-s who have rendered invaluable service in the devel- 

 opment of the Government vertebrate collections. The earliest of these 

 was Dr. Joseph Leidy. At intervals during the period from 1850 to 

 about 1873, most of the vertebrate material brought together under 

 governmental auspices was transmitted to liim in Philadelphia for 

 scientific investigation. These collections were later returned to the 

 Smithsonian and, as many of the specimens had been described and 

 illustrated, their importance was greatly enhanced. 



In the early seventies Prof. E. D. Cope began his collaborative work 

 ■with the Hayden survey. His entry into the western fossil fields in 

 1872 led to an immediate break in the hitherto friendly relations be- 

 i.ween Cope and Marsh, and eventually to the exclusion of Leidy from 



