350 m in depth. [...] Sea angels are gelatinous, mostly transparent and very small, with the largest species (Clione limacina) reaching 5 cm. Clione limacina is a polar species; those found in warmer waters are far smaller. Some species of sea angel 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. Their “wings” allow sea angels to swim much faster than the larger (usually fused) wings of sea butterflies.
Barrel-shaped body with paddle-like lateral wings; No external gills; Transparent body with orange-red colouration in the tail and horn-like mouth organs; Tentacles and hooks deployed during feeding; Reddish-brown visceral mass is seen through the body wall; Several subspecies and forms recognized, with differing shell shape and differeing polar/subpolar distribution.
An active swimmer while hunting for its shelled pteropod prey, primarily Limacina helicina; Feeding apparatus consists of 3 pairs of buccal cones (finger-like tentacles), 2 clusters of long hooks, and a toothed radula (a chain-saw like tongue) all normally hidden inside the head and body; Feeding apparatus is everted (pushed out) during feeding to extract the prey from their shells; A well-fed animal has a large dark gut.
(From EOL, 21 May 2011)