ADVERTISEMENT. 



This work (Bulletin No. 40) is one of a series of papers intended to 

 illustrate the collections belonging to the United States, and consti- 

 tuting the National Museum, of which the Smithsonian Institution 

 was placed in charge by the act of Congress of August 10, 184G. 



The publications of the National Museum consists of two series the 

 Bulletin, of which this is No. 46, in continuous series, and the Proceed- 

 ings, of which the sixteenth volume is now in press. A small edition 

 of each paper in the Proceedings is distributed in pamphlet form to 

 specialists in advance of the publication of the bound volume. 



The Bulletin of the National Museum, the publication of whicJi was 

 commenced in 1875, consists of elaborate papers based upou the col- 

 lections of the Museum, reports of expeditious, etc., while the Proceed- 

 ings facilitate the prompt publication of freshly-acquired facts relating 

 to biology, anthropology, and geology, descriptions of restricted ; groups 

 of animals and plants, the discussion of particular questions relative 

 to the synonymy of species, and the diaries of minor expeditions. 



Other papers, of more general popular interest, are printed in the 

 Appendix to the Annual Report. 



Full lists of the publications of the Museum may be found in the 

 current catalogues of the publications of the Smithsonian Institution. 



Papers intended for publication in the Proceedings and Bulletin of 

 the National Museum are referred to the Committee on Publications, 

 composed as follows: T. H. Bean (chairman), A. Howard Clark, R. E. 

 Earll, Otis T. Mason, Leonhard Stejneger, Frederick W. True, and 

 Lester F. Ward. 



S. P. LANGLEY, 

 Secretary of the Smithsonian Institution. 



WASHINGTON, August 31, 1893. 

 2 



