| | The families of non-marine molluscs of Britain and Ireland (slugs, snails and mussels) |
Morphology. Snails, with a conspicuous, spiral, univalve shell.
The animal with two pairs of tentacles (but the anterior pair small and inconspicuous). Eyes at the tips of the posterior tentacles. The mantle partly covering the shell when the animal is in motion.
The shell inoperculate; rising-spiral; 1.75–4 whorled; typically dextral; wider than high; 4.5–6 mm wide; height about 0.48–0.64 x the width; with the body whorl predominating and the spire small and short (the spire scarcely raised). The height of the spire about 0.04–0.15 x that of the shell. The spire obtuse. The shell cochleate, or very asymmetic about its vertical axis, with a large body whorl and a small, displaced spire (auriculate in Semilimax); shallowly sutured to deeply sutured. The whorls neither shouldered nor keeled. The aperture with neither teeth nor calluses. The shell without an umbilicus. The umbilicus small. The shell thin-lipped (the edge of the mouth thin and delicate, often with a non-calcified strip along its lower edge); thin and translucent; transparent, greenish, glossy; plain.
General biology, ecology. Terrestrial. V. pellucida ecologicaly catholic, in moist or dry coniferous and deciduous woods, quarries, stabilized dunes, etc., the others in and under moist leaf litter and fallen branches in woodland.
Hermaphrodite. Courtship involving exchanges of ‘love darts’ prior to mating; the darts chitinous.
Classification. Gastropoda; Pulmonata.
Representation in Britain and Ireland. “Glass snails”: Phenacolimax (1), Semilimax (1), Vitrina (1).
Illustrations. • Phenacolimax major, Semilimax pyrenaicus, Vitrina pellucida (Ellis). VITRINIDAE. 1. Semilimax pyrenaicus (Férussac), "Pyrenean Glass Snail". 2, Phenacolimax major (Férussac), "Greater Pellucid Glass Snail". 3 and 4, Vitrina pellucida (Müller), "Pellucid Glass Snail". From Ellis (1926, with shell dimensions added). • Vitrina pellucida and Semilimax pyrenaicus (Taylor). VITRINIDAE. 1. Semilimax pyrenaicus (Férussac), "Pyrenean Glass Snail", 5–6mm. 2, Vitrina pellucida (Müller), "Pellucid Glass Snail", 4.5–6.0mm. From Taylor (1914), shell dimensions from Kerney (1999). • Live Vitrina pellucida and Semilimax pyrenaicus, with Zonitidae and Euconulidae (Taylor). Live animals: VITRINIDAE. 1, Semilimax pyrenaicus (Férussac), "Pyrenean Glass Snail"; 2, Vitrina pellucida (Müller), "Pellucid Glass Snail". ZONITIDAE. 3, Oxychilus draparnaudii (Beck), "Draparnaud's Glass Snail"; 4, Nesovitrea hammonis (Ström), "Rayed Glass Snail"; 5, Oxychilus cellarius (Müller), "Cellar Snail"; 6, Oxychilus cellarius, var.; 7, Oxychilus helveticus (Blum), "Glossy Glass Snail", "Swiss Glass Snail"; 8, Aegopinella nitidula (Draparnaud), "Smooth Glass Snail", "Dull Glas Snail"; 9, Oxychilus alliarius (Miller), "Garlic Snail"; 10, Aegopinella pura (Alder), "Clear Glass Snail", "Delicate Glass Snail"; 11, Zonitoides excavatus (Alder), "Hollowed Glass Snail"; 12, Vitrea crystallina (Müller), "Crystal Snail"; 14, Zonitoides nitidus (Müller), "Shiny Glass Snail". EUCONULIDAE. 13, Euconulus agg., probably E. fulvus (Müller), "Tawny Glass Snail". From Taylor, 1914. • Vitrina pellucida, with Discidae, Euconulidae, Punctidae, Pyramidulidae, Valloniidae (Adams). PYRAMIDULIDAE. 1, Pyramidula rupestris (Draparnaud), "Rock Snail". PUNCTIDAE. 2, Punctum pygmaeum (Draparnaud), "Dwarf Snail". VALLONIIDAE. 3, Vallonia pulchella (Müller), "Smooth Grass Snail, Beautiful Grass Snail"; 4, Acanthinula aculeata (Müller), "Prickly Snail"; 5, Spermodea lamellata (Jeffreys), "Plated Snail"). DISCIDAE. 6, Discus rotundatus (Müller), "Rounded Snail, or Radiated Snail"). VITRINIDAE. 7, Vitrina pellucida (Müller), "Pellucid Glass Snail". EUCONULIDAE. 8, Euconulus fulvus agg., probably E. fulvus (Müller), "Tawny Glass Snail". From Adams (1896). • Vitrina pellucida (Reeve). VITRINIDAE. Vitrina pellucida (Müller), "Pellucid Glass Snail". From Reeve (1863, with approximate scale added).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The families of non-marine molluscs of Britain and Ireland (slugs, snails and mussels). Version: 5th August 2019. delta-intkey.com’.
