ADVh^KTlSEMKN'l' 



The present series, entitled " Smitlisonian Miscellaneous Collec- 

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

 tiie Smithsonian Institution in octavo form; those in quarto constitut- 

 ing the " Smithsonian 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 knowl- 

 edge. The octavo scries 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; reports of 

 explorations; aids to bibliographical investigations, etc., generally pre- 

 pared at the express request of the Jnsiitiition, and at its expense. 



Jn the Smithsonian Contributions l;o Knowledge, as well as in tlie 

 present series, each article is separately paged. Tlie 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 |)ub- 

 lished and largely distributed, years before their combination into 

 volumes. 



CHAS. D. WALCOTT, 

 8ecrelarij uf the Sniilksoniau InsiiLalioii. 



(Ill) 



