This bizarre little pelagic snail has a transparent, coiled shell into which the body can be completely withdrawn.   Due to its small size (shell diameter to 4 mm) and relatively transparent body, is easy to overlook.  The ventrally placed slender fin, which has a distinct sucker, is used for swimming.   Because of the shell, however, they are relatively inefficient swimmers, and must use continuous jerking movements of the fin to stay in position.  The sucker on the fin is used to hold veligers and small pteropod prey as the radula tears away pieces.  Atlanta can be found along the West Coast as far north as Vancouver Island, BC, and is the only atlantid likely to be found north of Point Conception.   Only a careful search in the contents of a plankton tow is likely to reveal their presence.

All photographs © David Wrobel and may not be used or copied without permission!