Drifters

Drifters (family vagusidae, wanderers) are a family of pelagic sea snails descended from Mystery Snails.  These snails can be found in the north and south Atlantic ocean gyres, areas full of stormrafts.  They evolved from invasive mystery snails dumped by aquarists in freshwater bodies on the eastern coast of America.

Biology

Drifters are about the size of a bladder snail.  Their shell has a wavy brown pattern in order to blend in.

Drifters, as stated earlier, are marine snails and are decked out with all the adaptations necessary for surviving saltwater.  Since they live in an environment where getting oxygenated water isn't as much of a problem, they fully rely on using gills and the lung is only present in juveniles and lost with age.  The young only have both respiratory organs because they spend their juvenile stage above the water on top of stormrafts.

Adults live inside and under stormrafts.  When they find themselves out at sea due to a storm or waves, they trap air in a small pocket in their shells and float until the sea carries them to a new raft.

Their diet consists of pretty much anything.  Most of it is sargassum but whenever theres a carcass in the area they'll get rid of it fast.  Their waste fertilizes the sargassum and other algae, keeping the mini-ecosystem running.

Behavior

Drifters are very sociable.  They usually tolerate other snails and even work together to get rid of carcasses.

Drifters are hermaphrodites and they mate in groups.  The snails form a ring while mating every snail carries eggs.  The eggs are deposited in clumps on top of the stormraft before all the adults die off.