Solvin Zankl / Sea butterfly {Clio recurva} (a thecosomate pteropod), Atlantic ocean

Solvin Zankl / Juvenile deep-sea pelagic snail (Limacina helicoides) captive specimen from off the coast of Cape Verde

Solvin Zankl / Sea butterfly or Thecosomata (Cavolinia uncinata) captive deep sea species from Atlantic Ocean off Cape Verde.

Solvin Zankl / Sea butterfly or Thecosomata (Clio chaptali) captive deep sea species Atlantic Ocean off Cape Verde.

Solvin Zankl / Sea butterfly (Peraclis bispinosa) captive deep sea species from Atlantic Ocean off Cape Verde.

Solvin Zankl / Sea butterfly (Diacria trispinosa) captive deep sea species from Atlantic Ocean off Cape Verde.

Solvin Zankl / Sea butterfly (Diacria trispinosa) deep sea species from Atlantic Ocean off Cape Verde. Captive.

Solvin Zankl / Sea butterfly (Cuvierina spoeli) deep sea species, captive from Atlantic Ocean off Cape Verde.

Solvin Zankl / Sea butterfly (Clio chaptali) captive deep sea species from Atlantic Ocean off Cape Verde.

Solvin Zankl / Sea butterfly (Hyalocylix striata) captive from Atlantic Ocean off Cape Verde.

Solvin Zankl / Wavy clio deep sea butterlfy (Clio recurva) deepsea species from Atlantic Ocean off Cape Verde. Captive.

Solvin Zankl / Sea butterfly / Thecosomata (Cuvierina spoeli) captive species from Atlantic Ocean off Cape Verde.

Solvin Zankl / Sea butterfly (Cavolinia uncinata) deep sea species from Atlantic Ocean off Cape Verde. Captive.

Juergen Freund / Sea butterfly, also known as Thecosomata or flapping snail, Lizard Island, Queensland, Australia, April 2008

Juergen Freund / Sea butterfly, also known as Thecosomata or flapping snail, Lizard Island, Queensland, Australia, April 2008

David Shale / Sea butterfly mollusc {Clio sp} Atlantic ocean. Deepsea species

Solvin Zankl / Sea butterfly (Limacina bulimoides) portrait, a swimming predatory sea snail, characterized by their wing-like parapodia allowing them to move through water like butterflies in the air. Observed durin...

Solvin Zankl / Sea butterfly (Cymbulia peronii) portrait, a pelagic sea snail which instead of an external calcareous shell, it has a pseudoconch made of conchioline, a cartilaginous tissue. They have also lost thei...

Tony Wu / Sea butterfly (Cavolinia uncinata),small pelagic mollusc, using nets of mucus to capture food. East China Sea, Kagoshima Prefecture, Japan.

Tony Wu / Sea butterfly (Cavolinia uncinata), small pelagic mollusc using nets of mucus to capture food. East China Sea, Kagoshima Prefecture, Japan.

Frederique Olivier / Sea butterflies / Pelagic swimming sea snails (Thecosomata) drifting with the current, Bellot Strait, Nunavut, Canada.

Solvin Zankl / Close up of Sea butterfly (Diacria trispinosa) translucent body, deep sea species from Atlantic Ocean off Cape Verde. Captive.

Solvin Zankl / Portrait of Sea butterfly (Diacria trispinosa) deep sea species from Atlantic Ocean off Cape Verde. Captive.

Solvin Zankl / Portrait of Sea butterfly / Thecosomata (Cuvierina spoeli) from Atlantic Ocean off Cape Verde. Controlled conditions.

Solvin Zankl / Portrait of planktonic Sea butterfly (Clio pyramidata) or Thecosomata Atlantic Ocean, close to Cape Verde.

Magnus Lundgren / Shelled pteropod (Diacria major) swimming with the tentacles out. Balayan Bay, off Anilao, Batangas, Philippines, Pacific Ocean

Solvin Zankl / Sea butterfly (Cymbulia sp.) originally classed as Pseudothecosomata. Cymbuliidae are pelagic sea snails, marine gastropod molluscs. Atlantic Ocean, close to Cape Verde. Controlled conditions.

Solvin Zankl / Sea butterfly (Cymbulia sp.) originally classed as Pseudothecosomata. Cymbuliidae are pelagic sea snails, marine gastropod molluscs. Atlantic Ocean, close to Cape Verde. Controlled conditions.

Solvin Zankl / Sea butterfly (Cymbulia peronii) originally classed as Pseudothecosomata. Cymbuliidae are pelagic sea snails, marine gastropod molluscs. Atlantic Ocean, close to Cape Verde. Controlled conditions.

Solvin Zankl / Sea butterfly (Cymbulia peronii) originally classed as Pseudothecosomata. Cymbuliidae are pelagic sea snails, marine gastropod molluscs. Atlantic Ocean, close to Cape Verde. Controlled conditions.

Magnus Lundgren / Wild Wonders of China / Flying sea snail (Clio sp.) photographed at night, Green Island, Taiwan. Lundgren