ADVERTISEMENT. 



■X 



This work (Bulletin No. 42) is one of a series of papers in tended to 

 illnstrate tbe collections belonging to the United States, and constitu- 

 ting 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 42, in continuous series, and the Proceed- 

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

 of each paper in the Proceedings is distributed in pamphlet forui 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 upon the col- 

 lections of the Museum, reports of expeditions, etc., while the Pro- 

 ceedings facilitate the prompt publication of freshly-acquired facts re- 

 lating 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 expedi- 

 tions. 



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 cur- 

 rent 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 Publications, 

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

 Earll, Otis T. Mason, John Murdoch, Leonhard Stejneger, Frederick 

 W. True, and Lester F. Ward. 



S. P. LAT>fGLEY, 

 Secretary of the Stnithsonian Institution. 



Washington, D. C, October 5, 1891. 



