ADVERTISEMENT. 



The scientific publications of the United States National Museum 

 consist of two series, the Proceedings and the Bulletins. 



The Proceedings, the first volume of which was issued in 1878, are 

 intended primarily as a medium for the publication of original, and 

 usually brief, papers based on the collections of the National Museum, 

 presenting newly acquired facts in zoology, geology, and anthropol- 

 ogy, including descriptions of new forms of animals, and revisions 

 of limited groups. One or two volumes are issued annually and 

 distributed to libraries and scientific organizations. A limited 

 number of copies of each paper, in pamphlet form, is distributed to 

 specialists and others interested in the different subjects as soon as 

 printed. The date of publication is recorded in the tables of contents 

 of the volumes. 



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

 series of separate publications comprising chiefly monographs of 

 large zoological groups and other general systematic treatises (occa- 

 sionally in several volumes), faunal works, reports of expeditions, 

 and catalogues of type-specimens, special collections, etc. The 

 majority of the volumes are octavos, but a quarto size has been 

 adopted in a few instances, in which large plates were regarded as 

 indispensable. 



Since 1902 a series of octavo volumes containing papers relating to 

 the botanical collections of the Museum, and known as the Contri- 

 butions from the National Herharium, has been published as bulletins. 



The present work forms No. 105 of the Bulletin series. 



William deC. Eavenel, 

 Administrative Assistant to the Secretary, 

 In charge of the United States National Museum. 



Washington, D. C, March 18, 1919. 



