ADVERTISEMENT 



The scientific publications of the National Museum include two 

 series, known, respectively, as Proceedings and Bulletin. 



The Proceedings, begun in 1878, is intended primarily as a medium 

 for the publication of original papers, based on the collections of 

 the National Museum, that set forth newly acquired facts in biology, 

 anthropology, and geology, with descriptions of new forms and revi- 

 sions of limited groups. Copies of each paper, in pamphlet form, 

 are distributed as published to libraries and scientific organizations 

 and to specialists and others interested in the different subjects. 

 The dates at which these separate papers are published are recorded 

 in the table of contents of each of the volumes. 



The Bulletin, the first of which was issued in 1875, consists of 

 a series of separate publications comprising monographs of large 

 zoological groups and other general systematic treatises (occasion- 

 ally in several volumes), faunal works, reports of expeditions, 

 catalogues of type-specimens, special collections, and other material 

 of similar nature. The majority of the volumes are octavo in size, 

 but a quarto size has been adopted in a few instances in which 

 large plates were regarded as indispensable. In the Bulletin series 

 appear volumes under the heading Contributions from the United 

 States National Herbarium, in octavo form, published by the 

 National Museum since 1902, which contain papers relating to the 

 botanical collections of the Museum. 



The present work forms No. 131 of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



Washington, D. C, February 23, 1926, 



