SMITHSONIAN INSTITUTION UNITED STATES NATIONAL MUSEUM Bulletin 73 AN ACCOUNT OF THE BEAKED WHALES OF THE FAMILY ZIPHIIDÆ IN THE COLLECTION OF THE UNITED STATES NATIONAL MUSEUM, WITH REMARKS ON SOME SPECIMENS IN OTHER AMERICAN MUSEUMS BY FREDERICK W. TRUE _Head Curator, Department of Biology, U. S. National Museum_ [Illustration: Smithsonian Institution] WASHINGTON GOVERNMENT PRINTING OFFICE 1910 BULLETIN OF THE UNITED STATES NATIONAL MUSEUM Issued September 28, 1910. 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 anthropology, 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 printed on each paper, and these dates are also recorded in the tables of contents of the volume. 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 (occasionally 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 _Contributions from the National Herbarium_, has been published as bulletins. The present work forms No. 73 of the _Bulletin_ series. Richard Rathbun, _Assistant Secretary, Smithsonian Institution, In charge of the United States National Museum._ Washington, D. C., June 1, 1910. TABLE OF CONTENTS.