

ADVERTISEMENT 



The scientific publications of the National Museum include two 

 series, known, respectively, as Proceedings and Bulletin. 



The Proceedings., begun in 18T8, is intended primarily as a me- 

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

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

 i)i()l(jgy, 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 organ- 

 izations and to specialists and others interested in the different 

 subjects. The dates at wdiich these separate papers are published 

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



The Bulletins., the first of which was issued in 1875, consist of a 

 series of separate publications comprising monographs of large zoo- 

 logical groups and other general systematic treatises (occasionally 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 

 ([uarto 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 Contributions from the United States 

 Xatlonal Heharlum, in octavo form, pviblished by the National 

 Museum since 1902, which contain papers relating to the Ijotanical 

 collections of the ]Museuui. 



The present work forms No. 151, of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



AVAsiiixciTox, I). C, March 17, 1931. 



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