ADVERTISEMENT. 
This work (Bulletin No. 24) is the thirtieth of a series of papers 
intended to illustrate the collections of natural history and ethnology 
belonging to the United States, and constituting the National Museum, 
of which the Smithsonian Institution was placed in charge by the act 
of Congress of August 10, 1546. 
It has been prepared at the request of the Institution, and printed by 
authority of the honorable Secretary of the Interior. 
SPENCER F. BAIRD, 
Secretary of the Smithsonian Institution. 
SMITHSONIAN INSTITUTION, 
Washington, November, 1882. 
