ADVERTISEMENT. 



The scientific publications of the National Museum consist of two 

 series — the Bulletin and the Proceedings. 



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

 of more or less extensive works intended to illustrate the collections 

 of the United States National Museum and, with the exception noted 

 below, is issued separately. These bulletins are monographic in scope 

 and are devoted principally to the discussion of large zoological and 

 botanical groups, faunas and floras, contributions to anthropology, 

 reports of expeditions, etc. They are usually 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. 



This work forms No. 57 of the Bulletin series. 



Since 1902 the volumes of the series known as " Contributions from 

 the National Herbarium" and containing papers relating to the 

 botanical collections of the Museum, have been published as bulletins. 



The Proceedings, the first volume of which was issued in 1878, are 

 intended as a medium of publication of brief original papers based 

 on the collections of the National Museum, and setting forth newly 

 acquired facts in biology, anthropology, and geology derived there- 

 from, or containing descriptions of new forms and revisions of lim- 

 ited groups. A volume is issued annually, or oftener, for distribution 

 to libraries and scientific establishments, and in view of the impor- 

 tance of the more prompt dissemination of new facts a limited edition 

 of each paper is printed in pamphlet form in advance. 



Charles D. Walcott, 

 Secretary of the Smithsonian Institution. 



Washington, U. S. A., June 15, 1907. 



