ADVERTISEMENT. 



The (.'xtension of the scope of the National Museum during recent 

 years and the activity of the c(jJlectors 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. 

 Tlie importance to science of prompt publication of descriptions of 

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

 of publications, entitled "Proceedings of the United States National 

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

 are published in pamphlet form as fast as completed .and in advance 

 of the bound volume. The present volume constitutes the nine- 

 teenth 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 tlie correspondence of the Smitlisonian 

 Institution. 



The Bulletin of the National :\[useum, the publication of which was 

 commenced in 1875, consists of elaborate papers based upon the collec- 

 tions of the Museum, reports of expeditions, 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 Anhual Report. 



Papers intended for publication in the Proceedings and Bulletin of 

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

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

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

 Stejneger, and Lester F. Ward. 



S. P. Langley, 

 Secretary of the Sniithsoiiian Institutio)i. 



II 



