ADVERTISEMENT. 



This work (Bulletin No. 50) is one of a sprios of papers intended to 

 illustrate the collections belon^-insi' to, or placed under the charofe of, 

 tlie Smithsonian Institution, and deposited in the United States National 

 iNluseuni. 



The pul)lications of the National Museum consist of two series: the 

 Bulletin and the Pt'oceedlm/.s. 



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

 of ela])orate papers, issued separately and based for the most part upon 

 collections in the National Museum, They are monographic in scope 

 and are devoted principall}' to the discussion of large zoological groups, 

 bibliographies of eminent naturalists, 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 fcAV instances in which a larger page was deeuied 

 indispensable. 



The Proceedings (octavo), the first volume of which was issued in 

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

 ac(juired facts in })iology, anthropology and geology, descriptions of 

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

 \olume of about 1,U00 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, chietiy of an ethnological character, describing collections in 

 the National Museum. 



Papers intended for publication by the National Museum are usually 

 referred to an Advisory Conunittee, 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 Smithsonian Institution. 

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



