ADVERTISEMENT 



The 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, antliropology, and geology, with descriptions of new forms 

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

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

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

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

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



The series of Bulletins, the first of wliich was issued in 1875, con- 

 tains separate publications comprising monographs of large zoologi- 

 cal groups and other general systematic treatises (occasionally in sev- 

 eral volumes), faunal works, reports of expeditions, catalogs of type 

 specimens and 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 wliich 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 vrork forms No. 168 of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



Washington, D. C, May 15, 1937. 



