To clarify further - as Jim or Bobbi said, "shell shops", meaning TOURIST
shops, do indeed get almost all of their shells either directly from the
Philippines, or from commercial shell importers (shell "warehouses") who get
them from the Philippines, literally by the ton.  However, SPECIMEN shell
shops and dealers necessarily obtain their shells from much more diverse, and
much more discriminating sources.
An amusing note on tourist shop shells - a lady in the local shell club once
brought to a meeting four postcards she had purchased in tourist shops during
her travels.  The legends along the bottom edges of the cards read
respectively as follows:
Card 1:  "Colorful shells of Florida"
Card 2:  "Colorful shells of Cape Cod"
Card 3:  "Colorful shells of Hawaii"
Card 4:  "Colorful shells of California"
Above the legend on each card was the exact same full color photograph of a
selection of colorful, common Philippine shells.
 
Paul M.