PREFACE. VII 



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

 Contributions to KnoAvledge." -The quarto series inchides memoirs, embrac- 

 ing the recoi'ds 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 bibliographical investi- 

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

 at its expense. 



"The position of a Avork in one or the other of the two series will some- 

 times depend upon 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 present 

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

 publication is that given on its special title ]>age, 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." 



The total number of papers published in the 23 volumes of "Miscellaneous 

 Collections" is 122, each volume averaging 882} pages, with an aggregate of 

 20,299 pages, 2,868 wood cuts, and 43 plates. 



3. Annual Reports. 



By the act of Congress organizing the Institution it was made the duty of 

 fhe " Board of Regents to submit at each session a report of the operations, 

 expenditures, and condition of the Institution." These Annual Reports 

 form a third series of Smithsonian publications. They consist of the reports 

 of the Secretary to the Board of Regents of the operations and condition of 

 the Institution ; the reports of committees of the Board ; reports of lectures ; 

 extracts from correspondence ; original or translated articles relating to the 

 history and progress of science, etc. 



The hrst report was submitted by the Board to the second session of the 

 29th Congress, 1847, and formed an octavo pamphlet of 38 pages. A similar 

 report was presented annually thereafter, varying in size from 64 pages to 

 326, printed in pamphlet form with paper covers up to 1853, when Congress 

 ordered the report to be bound in cloth. In the volume for that year the 

 essential portion^ of the contents of the preceding seven reports was reprinted, 



