thecosome pteropod or sea butterfly, Corolla spectabilis, is a pelagic gastropod related to slugs and snails, with a foot that is modified into a pair of locomotory wings, open ocean, pteropod, thecosome, sea life, ocean life, marine life, sea butterfly, plankton, Corolla spectabilis, gastropod, mollusc,jellyfish-like, Black Water Dive 6-27-15 with Pura Vida Divers on the Sirena out of Riviera Beach; Florida