ADVERTISEMENT. 



This work (Bulletin No. 51) is 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 

 J^ulletin and the Proceedings. 



The Bidletin^ 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. The,y are monographic 

 in scope and are devoted principalh" to the discussion of large zoolog- 

 ical groups, bibliographies of eminent naturalists, reports of expedi- 

 tions, etc. The JMilletins, issued onh^ as volumes with one exception, 

 are of octavo size, although a quarto form, known as the Special Bul- 

 letin, has been adopted in a few instances in which a larger page was 

 deemed indispensable. 



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

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

 acquired facts in biolog}", anthropology, and geolog}", 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 3'ear 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 Smithsonian Institution. 



Washington, U. S. A., April 4^^ 1902. 



