ADVERTISEMENT. 



The extension of the scope of the National Mnsenin during- recent 

 years and the activity of the collectors employed in its interest have 

 caused a great increase in the amount of material in its possession. 

 Many of the objects gathered are of a novel and important character, 

 and serve to throw a new light upon the study of nature and of man. 



The importance to science of prompt publication of descriptions of 

 this material led to the establishment, in 1878, of the inesent series 

 of publications, entitled " Proceedings of the United States National 

 Museum," the distinguishing peculiarity of which is that the articles 

 are published m pamphlet form as fast as completed and in advance of 

 the bound volume. The present volume constitutes the eighteenth of the 

 series. 



The articles in this series consist: First, of papers prepared by the 

 scientific corps of the National Museum; secondly, of papers by others, 

 founded upon the collections in the National Museum; and, finally, 

 of facts and memoranda from the correspondence of the Smithsonian 

 Institution. 



The Bulletin of the National 31 n scum, the publication of whicii was 

 commenced in 1875, consists of elal)orate papers based upon the collec- 

 tions of the Museum, reports of expeditions, etc., while the Proceedings 

 lacilitate the prompt publication of freshly-acquired facts relating to 

 biology, anthropology and geology, descri])tions 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 lo the Annual Report. 



Papers intended for publication m the Proceedings and lUilletin of 

 the National Museum are referred to the Advisory Committee on Pub- 

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

 Benjamin (editor), James E. Benedict, Otis T. 3Iason, Leonhard 



Steineger, and Lester F. Ward. 



S. P. Langlev, 



Secretary of the Smithsonian Institution. 



