The Academy of Natural Sciences of Philadelphia, 



April' 24, 1922. 



I hereby certify that the printed copies of the Proceedings for 1921 were 

 mailed as follows: 



Pages 1-32 September 12, 1921 



33-4S September 17, 1921 



49-64 October 6, 1921 



65-96 October 11, 1921 



97-192 October 14, 1921 



193-224 December 9, 1921 



225-240 December 24, 1921 



241-304 January 3, 1922 



305-352 January 4, 1922 



353-410 January 18, 1922 



417-436 January 23, 1922 



437-468 April " 6, 1922 



469-500 April 11, 1922 



501-532 April 13, 1922 



533-552 Apiil 24, 1922 



WILLIAM J. FOX, Editor. 



PUBLICATION COMMITTEE: 



Henry Skinner, M.D., Sc.D., Witmer Stone, A.M., Sc.D. 



Henry A. Pilsbry, Sc.D., William J. Fox, 



Milton J. Greenman, M.D. 

 The I'lrsifle?}!, John Cadwalader, A.M., LL.D., ex-officio. 



EDITOR: William J. Fox. 



