I love these Bubble Shells — my favourite colours all thrown into one beautiful, tiny slug. Like other members of the Aplustridae species, this slug lacks the ability to withdraw into its shell and is unable to protect itself by shutting the door (its operculum is non-existent). The animals documented here were all found in less than 3 meters of water (10 ft) grazing on algae in broad daylight in the North Kihei, Ma’alaea Harbour area of Maui. It seems that there are years where they are abundant and others where they are virtually invisible. To 40mm or 1.5 “. The Swollen Bubble Shell, or Hydatina aplustre is another beautiful Bubble Shell, that is rarely seen by snorkelers or tide poolers as it is diurnal and much smaller. For information on this family, check out Sea Slugs of Hawaii. Name was officially changed in July of 2021 from Micromelo undatus to Micromelo scriptus.