For 38 years, Rob Meyer and his family have walked the same stretch of beach along East Gulf Drive, but his stroll on Sunday with his son Michael was more fruitful than usual. Glancing down into the clear water between the shore and the first sandbar, Meyer saw something that looked different. Posed in the typical Sanibel stoop, Meyer scooped up a large shell he hadn’t found on previous trips to Sanibel.

“This seaweed-covered shell was freely moving with the current. I knew right away it was something different. When I couldn’t find it any of my shell guides I decided to bring it to the Museum to get expert advice,” said Meyer.

“I first visited the Museum the year it opened. It was fun to come back and share this with my children and see how things have changed,” Meyer said.

He was thrilled to find out that his mystery shell was Tonna galea (Linnaeus, 1758), or giant tun. The word tun means cask shell or wine jar. This gastropod is found in the deeper waters of the Caribbean and Mediterranean. Usually it is a caramel brown color; thin but strong, with broad prominent ribs or growth lines. It feeds on fish, crustaceans, sea cucumbers, and sea urchins. The animal has a large foot, is yellowish in color with black mottling, and small eyes at the base of the proboscis.

According to Dr. Jos H. Leal, the director of The Bailey-Matthews Shell Museum, “This snail produces babies that live for a long time in the larval stage, drifting in the water. This phenomenon allows babies to be transported to places that are distant from where their parents generally live. Is not unusual to find them on shores where they haven’t been found before.

“I’m always thrilled when shellers race to the museum to learn more about the unusual shells they find,” Dr. Leal said.