ADVERTISEMENT. 



The present series, entitled " Smithsonian Miscellaneous Collections," is 

 intended to embrace all the publications issued directly by the Smithsonian 

 Institution in octavo form ; those in quarto constituting the " Smithsonian 

 Contributions to Knowledge." The quarto series includes memoirs, embrac- 

 ing the records of extended original investigations and researches, resulting 

 in what are believed to be new truths, and constituting positive additions to 

 the sum of human knowledge. The octavo series is designed to contain 

 reports on the present state of our knowledge of particular branches of 

 science; instructions for collecting and digesting facts and materials for 

 research ; lists and synopses of species of the organic and inorganic world ; 

 museum catalogues ; reports of explorations ; aids to bibliograjjliical investi- 

 gations, etc., generally prepared at the express request of the Institution, 

 and at its exj>ense. 



The assignment of a work to one or the other of the two series will some- 

 times depend ujDon whether the required illustrations can be presented more 

 conveniently in the quarto or the octavo form. 



In the Smithsonian Contributions to Knowledge, as well as in the j>resent 

 series, each article is separately paged and indexed, and the actual date of 

 its publication is that given on its special title page, and not that of the 

 volume in which it is placed. In many cases works have been published, 

 and largely distributed, years before their combination into volumes. 



While due care is taken on the part of the Smithsonian Institution to 

 insure a proper standard of excellence in its publications, it will be readily 

 understood that it cannot hold itself responsible for the facts and conclusions 

 of the authors, as it is impossible in most cases to verify their statements. 



S. F. BAIRD, 



Secretary S. I. 



