Manufactured in the United States of America Dover Publications, Inc. 180 Varick Street New York, N. Y. 10014 ADVERTISEMENT The scientific publications of the National Museum include two series, known, respectively, as _Proceedings_ and _Bulletin_. The _Proceedings_, 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 revisions 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 _Bulletin_, the first of which was issued in 1875, consists of a series of separate publications comprising monographs of large zoological groups and other general systematic treatises (occasionally in several volumes), faunal works, reports of expeditions, catalogues 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 _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. 142 of the _Bulletin_ series. ALEXANDER WETMORE, _Assistant Secretary, Smithsonian Institution_. WASHINGTON, D. C., _November 15, 1927_. TABLE OF CONTENTS PAGE