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Möller, 1841

Full name (Van der Spoel et al., 1997): Limacina retroversa (Fleming, 1823) subsp. retroversa (Fleming, 1823) forma balea Möller, 1841

Description
Aa small, shelled, pelagic thecosomatous pteropod with a left-coiled shell, 0.3 cm in diameter. [L.r.balea-ph]. The spire is highly coiled. It has 9 transparent whorls with a brown to purple hue. There is no umbilical keel. Faint transverse striae are present. [Limacina r. balea].
Shell with a higher coil than in the forma retroversa [Limacina spp.] with a smaller top angle, the number of whorls is larger, up to 9. The whole shell shows a rather coarse spiral striation and numerous transverse growth lines. The suture is clear. The shell aperture is not so very large and not regularly rounded, but somewhat oblique. Umbilicus is narrow and deep. A wing protrusion is present
Radula formula 1-1-1, composed of about 8 transverse rows [L.r.balea-rad].
Juveniles have a small left coiled shell. A special description is not available.

Colour
The thin transparent shell is light rose.

Size
Shell height up to 7 mm, average maximum diameter 2.4 mm.

Ecology
It is found in temperate waters of the North Atlantic where it feeds on phytoplankton, it is a mucus feeder. The temperature range is (3)11-18°C and the salinity range is 31.8-35ä.

Depth range
Epipelagic

Distribution in the North Sea
Might be found in the northern North Sea, entered from the NE Atlantic.

World distribution
This form is found in cold waters of N Atlantic between 30° and 75°N.

[After Van der Spoel et al., 1997]

Form Limacina retroversa f. balea