ADA^ERTISEMENT. 



Til is work (Bulletin No. 49) is one of a scries of papers intended 

 to illustrate the collections belongiufi; to the TTnited States, and con- 

 stituting 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 consist of two series — 

 the Bulletins, of which this is No. 49, in continuous series, and the 

 Proceedings, of which the eighteenth volume is now in iiress. A 

 small edition of each j)aper in the Proceedings is distributed in pam- 

 phlet form to specialists, in advance of the publication of the bound 

 volume. 



The Bulletins of the National Museum, the publication of which 

 was commenced in 1875, consist of elaborate papers based uj^on the 

 collections of the Museum, reports of expeditions, etc., while the 

 Proceedings 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 i^ublications 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 Bulletins 

 of the National Museum are referred to the Committee on Publica- 

 tions, composed as follows: Frederick W. True (chairman), Marcus 

 Benjamin (editor), J. E. Benedict, Otis T. Mason, Leonhard Stej- 



neger, and Lester F. Ward. 



S. P. Langley, 



Secretary of the Smitlhsonian Institution. 



Washington, 1). C, August 1, 1896. 

 II 



