Image of hump-backed cowrie

Description:

Possibly a Tonnidae but this is just a guess. It was washed up in a tidepool and pretty beaten up. The edge of the shell had a lot of breaks. I put it in a container with seawater to take it back for imaging. Large dark body with a very thin shell. Definitely not a cowrie or a cone snail. ---update, quite possibly a bulla-stage juvenile cowrie.