v4o 



ADVERTISEMENT, 



The present series, entitled " Smithsonian Miscellaneous Collec- 

 tions," is intended to embrace all the publications issued directly by 

 the Smithsonian Institution in octavo form ; those in quarto consti- 

 tuting the " Smitlisonian Contributions to Knowledge." The quarto 

 series includes memoirs, embracing 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 

 tf 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 

 investigations, etc., generally prepared at the express request of the 

 Institution, and at its expense. 



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-page, and 

 not that of the volume in which it is jjlaced. In many cases works 

 have been published and largely distributed, years before their combi- 

 nation into volumes. 



S. P. LANGLEY, 



Secretary S. I. 



(iii) 



