AD^'ERTISEMEXT 



The scientific publications of the National Museum include two 

 series, known, respectively, as Proceedings and Bulletin. 



The Proceedings series, begun in 1S7S. 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 biol- 

 ogy, 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 hbraries and scientific organizations 

 and to specialists and otibers interested in the different subjects. 

 The dates at which these separate papers are published are recorded 

 in tie table of contents of each of the volumes. 



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

 tains separate pubUcations comprising monographs of large zoologi- 

 cal groups and other general systematic treatises (occasionally in 

 several volumes', fajimai works, reports of expeditions, catalogues of 

 type specimens ^nd 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 jron\ the United States National 

 Herbarium, in octavo form, published by the National Maseum since 

 1902, which contain papers relating to the botanical collections of 

 the Museum. 



The present work forms No. 160 of the Bulletin series. 



Alexaxdee Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



Washtn-gton, D. C, March 31, 1932. 



