VvV>r. U^-^.^opy 



ADVERTISEMENT 



The Smithsonian Miscellaneous Collections series contains, since the 

 suspension in 1916 of the Smithsonian Contributions to Knowledge, 

 all the publications of the Institution except the Annual Report, the 

 annual pamphlet describing the Institution's field-work, and occasional 

 publications of a special nature. As the name of the series implies, its 

 scope is not limited, and the volumes thus far issued relate to nearly 

 every branch of science. Papers in the fields of biology, geology, 

 anthropology, and astrophysics have predominated. 



C. G. Abbot, 

 Secretary of the Siiiithsouiau Institution. 



(iii) 



