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Family Trichotropidae

SHELL thin, turbinated; spire elongated; the keeled whorls bearing an epidermal fringe of hairs; aperture roundish, angled below; lip sharp; operculum laminated; foot elongated; head broad; radula well developed; eyes on sides of tentacles.

Genus TRICHOTROPIS, Brod.

Characters of the family. Fifteen species in arctic waters.

The Northern Hairy-keel (T. borealis, Brod. and Sby.) has a thin little colourless spire, an inch long or less, with strongly keeled whorls separated by deep but narrow sinuses. In life there is a thin brownish epidermis which bears a row of hairs. Dead specimens soon lose these hairs.

Habitat.--Japan, Northern Europe, Greenland to Massachusetts.

T. cancellata, Hds., a trifle larger, checkered by longitudinal ribs crossing the spiral ones, may be but the western form of T. borealis.

Habitat.--Alaska to Vancouver Island.