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 collections 

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

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

 visions 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 series of Bulletins^ the first of which 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, 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 Oontnhutions from the United States National Herharium^ 

 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. 198 of the Bulletin series. 



Alexander Wetmore, 

 Secretary^ Smithsonian Institution. 

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