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 Mu- 

 seum, presenting newly acquired facts in zoology, geology, and an- 

 thropology, including descriptions of new forms of animals, and revi- 

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

 distributed to libraries and scientific organizations. A limited num- 

 ber of copies of each paper, in pamphlet form, is distributed to spe- 

 cialists and others interested in the different subjects, as soon as 

 printed. The date of publication is recorded in the tables of con- 

 tents 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 S3"stematic treatises (occa- 

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

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

 jority 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 Contribu- 

 tions from the National Herbarium, has been published as bulletins. 



The present work forms No. 128 of the Bulletin series. 



William deC. Ravenel. 

 Administrative Assistant to the Secretary, 

 In Charge of the United States National Museum. 



Washington, D. C, March 18, 1924. 



