ADVERTISEMENT 



Tlie scientific publications of the National Museum include two 

 series, known, respectively, as Proceedings and Bulletin. 



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

 medium for the publication of original papers, based on the collec- 

 tions of the National Museum, that set forth newly acquired facts 

 in biology, anthropology, and geology, with descriptions of new forms 

 and revisions of limited groups. Copies of each paper, in pamphlet 

 form, are distributed as published to libraries and scientific organi- 

 zations and to specialists and others interested in the different sub- 

 jects. The dates at which these separate papers are published are 

 recorded in the table of contents of each of the volumes. 



Tlie series of Bulletins, the first of which was issued in 1875, 

 contains separate publications comprising monographs of large 

 zoological groups and other general systematic treatises (occasionally 

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

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

 lar 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 vol- 

 umes under the heading C ontrihutions from the United States Na- 

 tional Eerharium, 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. 173 of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



Washington, D. C December 12, 1938. 



