Hi Sophie, Land snails are not my forte, but I believe the shells in the last picture (#17, 18, 19) are Achatina, not Amphidromus. I think they are probably the widespread Achatina fulica. Also, I believe that shells #12, 13, and 16 are juveniles of that same species. The other shells pictured with them are Amphidromus, but I'll leave it to the experts to say which species. Shell #5 appears to be an immature fresh water snail of the family Ampullariidae, genus Pila or Pomacea, and shells #6 and 7 may also be members of that group. Good luck. Paul M.