Living in the lagoon area.
These are opercula from Queen Conchs. A fisher had dumped them on the beach from his fishing boat I presume.
They cut the columellar muscle through the shell in the boat while they are out at sea, taking the soft parts and dumping the shells overboard.
That makes it hard to know if they are breaking the law by taking subadult conchs, which is almost always the case unfortunately.
The Neotaenioglossa is an taxonomic name for a large group of mostly sea snails. The name was originally created by Haller in 1882. Ponder and Warén (1988), and Marquet (1997), assigned this name to the superorder Caenogastropoda. ITIS considers the order Neotaenioglossa to be a synonym of Cerithioidea Férussac, 1819 .