Dance Rattle "Ceco'q" Item Number: E9255-0 from the National Museum of Natural History
FROM CARD: "A BOX ENCLOSING PEBBLES OF CARVED WOOD, HAVING THE FORM OF A LONG CLAM, PARTLY OPEN WITH THE FLESH DRAWN BACK TOWARDS THE HINGE NEARLY HALF THE LENGTH OF THE SHELL. THE BOX IS FORMED IN THE FLESH PART."Listed on page 42 in "The Exhibits of the Smithsonian Institution at the Panama-Pacific International Exposition, San Francisco, California, 1915", in section "Arts of the Northwest Coast Tribes".