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, 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. 



The 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 sev- 

 eral volumes), faunal works, reports of expeditions, catalogues 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 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. 100, volume 12, of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



Washington, D. C, April 17, 1933. 

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