ADVERTISEMENT. 



This work (Bulletin No. 50) i.s one of a series of papers intended to 

 illustrate the collections belonging to, or placed under the charge of, 

 the Smithsonian Institution, and deposited in the United States National 

 Museum. 



The publications of the National Museum consist of two series: the 

 Bulletin and the Procendingii. 



The Bulletin^ publication of which was commenced in 1875, is a series 

 of elaborate papers, issued separately' and based for the most part upon 

 collections in the National Museum. They are monogi-aphic in scope 

 and are devoted principally to the discussion of large zoological groups, 

 bibliographies of eminent naturalist^, reports of expeditions, etc. The 

 Bulletins, issued only as volumes with one exception, are of octavo 

 size, although a quarto form, known as the Special Bulletin, has 

 been adopted in a few instances in which a larger page was deemed 

 indispensable. 



The Proceedlru/K (octavo), the first volume of which was issued in 

 1878, are intended primarily as a medium of publication for newly 

 acquired facts in biologj', anthropology and geology, descriptions of 

 new forms of animals and plants, discussions of nomenclature, etc. A 

 volume of about 1,000 pages is issued annually for distribution to 

 libraries, while a limited edition of each paper in the volume is printed 

 and distributed in pamphlet form in advance. 



In addition, there are printed each year in the second volume of the 

 Smithsonian Report (known as the ' ' Report of the National Museum ") 

 papers, chiefly of an ethnological character, describing collections in 

 the National Museum. 



Papers intended for publication by the National Museum are usually 

 referred to an Advisory Committee, composed as follows: Frederick 

 W. True (chairman), William H. Holmes, George P. Merrill, James 

 E. Benedict, Otis T. Mason, Leonhard Stejneger, Lester F. Ward, and 

 Marcus Benjamin (editor). 



S. P. Langley, 

 Secretary of the SmitJisoniati Institution. 



Washington, U. S. A., July i, 1901. 



