On Friday, May 27, Dyanne Wagner, the aquarium specialist at the Marine Science Center, came into my office to report an unusual find. She wanted to know if snails could live without a shell. Dyanne had observed, what she believed to be an Eastern Mud Snail, without a shell, in one of her tanks in the Wet Lab. Since I had never heard of this phenomenon, and thinking it could be a Nudibranch, I went down the hall to check it out.

     I was soon to discover it was in fact a mud snail, Ilyanassa obsoleta (Say, 1822), sans shell, and acting very normal. I lifted the snail out of the tank and placed it on the palm of my hand. The snail immediately righted itself and began investigating my palm. When I put it back on the bottom of the aquarium, it made tracks for the glass and crawled up the side. Dyanne said she had been observing it for several days and it usually stayed at the top of the aquarium, much like the normal snails. Feeling that the event was noteworthy, I photographed our unusual snail.

     I called both Dr. Harry Lee and Dr. Tucker Abbott, noted shell authorities, to see if they had heard of this before, Dr. Lee had read of an account in the Hawaiian Shell News about a Textile Cone (Conus textile) in an aquarium in Hawaii that shed its shell and lived for seven days. Go To Naked Cone

     Dr. Abbott also referred to an article by Dr. Joe Rosewater, which appeared in the Nautilus about 15 years ago on this phenomenon. Dr. Abbott said, "I don't know why this happened, but the columella muscle becomes detached, and the shell is shed."

"Naked Mud Snail"