ADVERTISEMENT. 



THE present catalogue is intended to embrace all the articles 

 published by the Smithsonian Institution since its organization in 

 1846. For the first few years nothing was issued but pamphlets 

 explanatory of the plan of the Institution, and brief annual reports 

 of the proceedings of the Regents, and it was not until after 1849 

 that the following regular series were established, viz : 



1st. A quarto series entitled " Smithsonian Contributions to 

 Knowledge," issued in volumes, each embracing one or more sepa- 

 rate articles. 



2d. An octavo series, entitled "Smithsonian Miscellaneous Col- 

 lections." 



3d. Another octavo series, consisting of the Annual Reports of 

 the Institution to Congress, called "Smithsonian Reports," and 

 printed at the expense of the government. 



The Smithsonian Contributions to Knowledge include memoirs 

 embracing the records of extended original investigations and re- 

 searches resulting in what are believed to be new truths, and con- 

 stituting positive additions to the sum of human knowledge. The 

 series of Smithsonian Miscellaneous Collections is designed to con- 

 tain 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 ex- 

 plorations ; aids to bibliographical investigations, etc., generally 

 prepared at the express request of the Institution, and at its ex- 

 pense. The position of a work in one or the other of these two 

 series will sometimes depend upon whether the required illustra- 

 tions can be presented more conveniently in the quarto or the 

 octavo form. 



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