Victor et Desirée FALZON le 16/09/22
Hi,
I found these worm snails under a pebble in shallow water (<1m). Quite common. They are 5mm across and hard. Thank you very much for your help!
Desirée
Yann QUERREC le 19/09/22
Hi,They are not gastropods. I think you're talking about these tube-dwelling anelids. They are spirorbs.