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 revi- 

 sions 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, 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 speci- 

 mens, 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 indis- 

 pensable. 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. 189 of the Bulletin series. 



Alexander Wetmore, 

 Secretary, Smithsonian Institution. 



