| | 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. Eyes at the tips of the posterior tentacles. The jaw arcuate, with a vertical central keel ending in a median projection on the lower edge (cf. Limacidae, etc.).
The shell inoperculate; rising-spiral (but often only slightly raised); 3.5–6(–7) whorled; typically dextral; wider than high; 2.2–15 mm wide; height about 0.43–0.59 x the width; with the body whorl predominating and the spire small and short. The height of the spire about 0.1–0.18 x that of the shell, or 0.2–0.28 x that of the shell (Zonitoides). The spire obtuse. The shell more or less discoid, or cochleate; deeply sutured. The body whorl moderately convex to very strongly convex. The whorls of the spire feebly convex to moderately convex. The whorls neither shouldered nor keeled. The aperture with neither teeth nor calluses. The shell with an umbilicus to without an umbilicus. The umbilicus small to large and wide (variable in depth, with, and symmetry). The shell thin-lipped (the mouth edge delicate, not deflected); in life, mostly thin and translucent (and usually glossy, but often becoming opaque after death of the animal); often clear horn-coloured, fawn, brownish or whitish; plain. Morphological comments. The body of the animal is often tinted bluish.
General biology, ecology. Terrestrial. In vegetation and ground litter, under logs and stones, etc., in diverse habitats.
Hermaphrodite. Courtship involving exchanges of ‘love darts’ prior to mating (the Zonitoides species), or not involving ‘love darts’; the darts calcareous.
Classification. Gastropoda; Pulmonata.
Representation in Britain and Ireland. “Glass snails” and “Garlic snails”: Aegopinella (2), Nesovitrea (2), Oxychilus (4), Vitrea (3), Zonitoides (2).
Illustrations. • Aegopinella nitidula, Oxychilus alliarius, O. cellarius, O. draparnaudii, O. helveticus (Taylor). Cleaned shells of ZONITIDAE. 1. Oxychilus draparnaudii (Beck), "Draparnaud's Glass Snail", 11–15mm. 2, Oxychilus cellarius (Müller), "Cellar Snail", 9–12(-14)mm. 3, Aegopinella nitidula (Draparnaud), "Smooth Glass Snail", "Dull Glass Snail", 8–10mm. 4, Oxychilus helveticus (Blum), "Glossy Glass Snail", "Swiss Glass Snail", 8–10mm. 5, Oxychilus alliarius (Miller), "Garlic Snail", 5.5–7.0mm. From Taylor (1914), with mature shell diameters from Kerney (1999). • Aegopinella pura, Nesovitrea hammonis, Vitrea contracta, V. crystallina, Zonitoides excavatus, Z. nitidus (Taylor). ZONITIDAE. 1. Aegopinella pura (Alder), "Clear Glass Snail", "Delicate Glass Snail", 3.5–4.2mm. 2, Nesovitrea hammonis (Ström), "Rayed Glass Snail", 3.5–4.2mm. 3, Vitrea crystallina (Müller), "Crystal Snail", 3–4mm. 4, Vitrea contracta (Westerlund), "Milky Crystal Snail", 2.2–2.5mm. 5, Zonitoides nitidus (Müller), "Shiny Glass Snail", 6–7mm. 6, Zonitoides excavatus (Alder), "Hollowed Glass Snail", 5.3–6.0mm. From Taylor (1914), mature shell dimensions from Kerney (1999). • Live animals: Aegopinella, Nesovitrea, Oxychilus, Vitrea, Zonitoides (Taylor). ZONITIDAE. 3, Oxychilus draparnaudii (Beck), "Draparnaud's Glass Snail" (11–15mm); 4, Nesovitrea hammonis (Ström), "Rayed Glass Snail", 3.5–4.2mm; 5, Oxychilus cellarius (Muller), "Cellar Snail", 9–12(-14)mm; 6, Oxychilus cellarius, var.; 7, Oxychilus helveticus (Blum), "Glossy Glass Snail", "Swiss Glass Snail", 8–10mm; 8, Aegopinella nitidula (Draparnaud), "Smooth Glass Snail", "Dull Glass Snail", 8–10 mm; 9, Oxychilus alliarius (Miller), "Garlic Snail", 5.5–7mm; 10, Aegopinella pura (Alder), "Clear Glass Snail", "Delicate Glass Snail", 3.5–4.2mm; 11, Zonitoides excavatus (Alder), "Hollowed Glass Snail", 5.3–6.0; 12, Vitrea crystallina (Müller), "Crystal Snail", 3–4mm; 14, Zonitoides nitidus (Müller), "Shiny Glass Snail", 6–7mm. VITRINIDAE. 1, Semilimax pyrenaicus (Férussac), "Pyrenean Glass Snail", 5–6mm; 2, Vitrina pellucida (Müller), "Pellucid Glass Snail", 4.5–6mm. EUCONULIDAE. 13, Euconulus agg., probably E. fulvus (Müller), "Tawny Glass Snail", 2.3–3.5mm. From Taylor (1914), mature shell dimensions from Kerney (1999). • Aegopinella, Nesovitrea, Oxychilus, Vitrea, Zonitoides (Adams). ZONITIDAE. 5, Oxychilus cellarius (Müller), "Cellar Snail"; 6, Oxychilus alliarius (Miller), "Garlic Snail"; 7, Oxychilus helveticus (Blum), "Glossy Glass Snail, or Swiss Glass Snail". 8, Aegopinella nitidula (Draparnaud), "Smooth Glass Snail, Dull Glass Snail"; 9, Aegopinella pura (Alder), "Clear Glass Snail, Delicate Glass Snail". 10, Nesovitrea hammonis (Ström), "Rayed Glass Snail". 11, Zonitoides nitidus (Müller), "Shiny Glass Snail"; 12, Zonitoides excavatus (Alder), "Hollowed Glass Snail"; 13, Vitrea crystallina (Müller), “Crystal Snail”. From Adams (1896). • Love darts of Zonitoides, with some from Helicidae (Taylor). Love Darts. ZONITIDAE. 9, Zonitoides excavatus, side and front views, and a further enlargement of the tip. HELICIDAE. 1, Cernuella virgata, with section showing the lateral wings. 2, Helicogona lapicida, with section of the lanceolate head. 3, Helix pomatia, sectioned to show the four wings. 4, Cepaea hortensis, sectioned to show the complex wings. 5, Cepaea nemoralis, showing transverse septa joining the four simple wings, and with diagrammatic transverse sections. 6, Helix aspersa. 7, Theba pisana, with a section through the mid-region. 8, Arantia arbustorum, with section through the lenticular head. From Taylor (1907 & 1914), with approximate dart lengths added. • Aegopinella, Neesovitrea, Oxychilus, Vitrea, Zonitoides (Reeve). ZONITIDAE. 1, Oxychilus cellarius (Müller), "Cellar Snail". 2, Oxychilus alliarius (Miller), "Garlic Snail". 3, Aegopinella nitidula (Draparnaud), "Smooth Glass Snail", "Dull Glass Snail". 4, Aegopinella pura (Alder), "Clear Glass Snail", "Delicate Glass Snail". 5, Nesovitrea hammonis (Ström), "Rayed Glass Snail". 6, Zonitoides nitidus (Müller), "Shiny Glass Snail". 7, Zonitoides excavatus (Alder), "Hollowed Glass Snail". 8, Vitrea crystallina (Müller), "Crystal Snail". From Reeve (1863), with shell diameters 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’.
