These pelagic snails are not at all closely related to the pelagic heterobranch opistobranchs such as the sea angels and sea butterflies.
12.
"' Cymbuliidae "'is a family of pelagic sea snails or " sea butterflies ", marine gastropod mollusks in the superfamily Cymbulioidea.
13.
"' Desmopteridae "'is a family of pelagic sea snails or " sea butterflies ", marine gastropod mollusks in the superfamily Cymbulioidea.
14.
"' Peraclidae "'is a family of pelagic sea snails or " sea butterflies ", marine gastropod mollusks in the superfamily Cymbulioidea.
15.
""'Limacina " "'is a genus of swimming predatory sea snails commonly known as sea butterflies in the family Limacinidae.
16.
The genus " Lepeta " uses the whole of the mantle cavity as a respiratory surface, while many sea butterflies respire through their general body surface.
17.
The sea butterfly uses a high angle of attack of approximately 45-50 degrees to generate lift, and it beats its wings 4 to 10 times per second.
18.
This family is part of a larger group which is commonly known as the "'sea butterflies "'because they swim by flapping what appear to be small " wings ".
19.
""'Clio pyramidata " "'is a species of sea butterfly, a floating and swimming sea snail, a pelagic marine gastropod mollusk in the family Cliidae.
20.
Some species of sea angels feed exclusively on sea butterflies; the angels have terminal mouths with the radula common to mollusks, and tentacles to grasp their prey, sometimes with suckers similar to cephalopods.
