Snails in a Sussex garden

A few years ago, I made a careful investigation of the snail fauna of our garden, in West Barnham, Sussex; and I found the results surprisingly interesting. The garden was of about 2.5 acres, situated a quarter of a mile north-west of Barnham railway station. I acquired the house in 1945, and I gathered that the neighbourhood had been open meadowland till developed about 50 years ago. Half our acreage consisted of neglected garden and orchard and the rest was still original meadowland, with Sweet Vernal Grass (Anthoxanthum odoratum L.) growing there. Several factors rendered our garden an unpromis¬ing terrain in which to find any large snail fauna. It was neither on nor near to the bare chalk beloved by so many species, and the soil was brick- earth with only a small lime content. There was no diversification of terrain, such as ditch, pond, bank or old ruinous wall which might favour extra species, and finally the area was dominated by pine trees, so that the ground beneath was strewn with the needles, the resinous content of T/hich is, I believe, dis¬liked by most snails. Yet, despite these apparently adverse factors, I found a fauna of 22 species (excluding the slugs) in the garden. In this article, I shall use the classification and nomenclature employed by A. E. Ellis, 'British Snails', 1926.

Vertigo pygmaea (Draparnaud) was found at two spots in the meadowland, and collected by shaking moss over paper and searching the residue with a hand lens. Lauria cylinarica (E.M. da Costa) may have been a recent introduction, as I only found it on a newly constructed rockery and on the spot where the rocks had been temporarily stored prior to the work. The rocks, irregular concretions of Eocene Bognor Rock, had come from an old rockery in front of a Georgian terrace in Bognor Regis, where, within reach of the sea spray, it had doubtless existed since Regency times. In deep earth-filled pot-holes in the rocks, I found bleached and crumbling shells of this species.

ValIonia costata (Muller), and V. pulchella (Muller) were both collected by searching under stones, bricks, etc., and by placing all unwanted shells of larger size in a box and shaking it, a trick which often yields the tiny species, which have been hiding inside the larger empty shells. Coecillioides acicula (Muller) was also present in the garden, and I have found it, above ground, by searching the fruiting heads of moss on the rockery stones on bright spring mornings. Cochlicopa lubrica (Muller) was common everywhere in damp spots. Ena obscura (Mttller) is possibly another recent introduction, as I have only found it on some heaps of local road grit brought in to improve the soil, though, alternatively, it may be native to the garden and may have congregated on these favourable raised sites. Puneturn pygmeum (Muller) occurs commonly amongst moss in the meadowland, with V. pigmaea, and is collected by the same method; its satin-like surface is characteristic.

Goniodiscus rotundatus (Muller), so widely and generally distributed, is uncommon in our garden, but I found a thriving colony under the staging in our conservatory, a brick structure with a concrete floor. Clausilia rugosa Draparnaud was very scarce with us; I have only found it on the heaps of road grit and on a heap of builders rubble from a very different source. This again suggests that both this species and Ena obscn^a are native to the garden, and have selected the most favourable sites in which to congregate. Belicella caperata (Montagu) was found plentifully in the meadowland, with one example of the variety ornata Pickard. Theba cantiana (Montagu) was common in the more open parts, amongst rough herbage; the punctate ornament of the pink lining of the aperture is a feature I have not seen mentioned.

Trichia hispida (Linne) was one of our most abundant species, occurring in damp spots. I found one example of its variety depressula Dumont & Mortillet. Our commonest species is unquestionably Trichia striolata (C. Pfeiffer), with its varieties alba Moquin-Tandon, rubens Moquin-Tandon and albocinctus Cockerell, sharply keeled around the periphery. Cepaea hortensis (Mtiller) was fairly frequent, despite the number of Song Thrushes in the garden. To the human collector, the typical banded form outnumbers the unband¬ed form of the variety lutea Pickard by ten to one, but around the thrushes' anvil stones the yellow shell predominates. Helix aspersa Mtlller is not common in the garden, though a colony wrought much havoc amongst our Crinums.

Retlnella radiatula (Alder) occurs with V. pygmaea and Puneturn pygmeum amongst moss in the meadowland, and was obtained by the same method of collect¬ing. PLetinella nldidula (Draparnaud) was common throughout the garden, mainly in the damp spots. Oxychilus cellarius (Mtlller) is fairly common under stones in damp places. Judging by the surrounding district, I am fortunate to have my own particular favourite species, Oxychilus lucidus (Draparnaud), in our garden, for it seems scarce in this part of West Sussex. We found it under stones and similar hiding places. This snail evidently falls a frequent victim to mice, judging by the characteristic type of damage noted in dead shells. Vitrea crystalline, (Mtlller) was fairly frequent, in damp spots under stones, and was also obtained from boxes of larger shells, shaken as already described. Vitrina pellucida (Mtlller) is more common, occurring in similar situations throughout the garden.

E. M. Venables