The Lapidary snail

At the weekend my sister and I went for a little stroll on one of the limestone hills around Bath. I was there for a recce for my impending MSc dissertation. That will be on the plants. But naturally I got distracted.

We were poking about amongst the boulders (the site has been much quarried for the stone that built Bath's famous architecture) and I found a strangely shaped snail. It's rather flat and has a curious trumpety opening (aperture). It also has a distinct keel (it's 'carinated'). The surface is very textured.

I used this key from BRERC to identify it (it was relatively easy, which was encouraging): it's the Lapidary snail, Helicigona lapicida. 'Lapidary' means to do with cutting rocks or precious stones. My Victorian snail guru Mr Adams says "The name stone-cutter" is due to its supposed habit of boring into rocks. The idea is, of course, erroneous, but it does ensconce itself in crevices of rocks, whence it emerges after rain."

I will be using the word 'ensconce' wherever possible today.

Other theorists (the author of the eminently tattooable title 'Shell Life') have it that the species looks like a grinding wheel for polishing precious stones (like this one). Also pretty believable. But why should you care about etymology? I can only suggest that knowing all this might help in remembering the creature's Latin name. Which is essential if you're to impress fellow naturalists.

Something seems to have made a home in the central 'umbilicus'.

The species belongs to the family Helicidae, which includes the more rounded and familiar species like the Garden snail Helix aspersa (shells of which I also found):

CC image by Sid Mosdell.

and the beautifully colourful and variably stripey Brown-lipped snail Cepaea nemoralis:

CC image by Mad Max.

There were also shells of the White-lipped snail Cepaea hortensis,  

CC image by Martin Cooper.

the very flat and tiny Rounded snails Discus rotundatus,  

CC image by FW Schultes.

 and maybe a little Vitrina pellucida, a transparent 'glass snail'.

CC image by FW Schultes

And all these from a short while poking about in the leaf litter on top of the rocks. So I think a snail shell collection could be very viable if you're still looking for something to choose. Looking back through this blog I've found and identified 11 species without too much strenuousness or pain - I wasn't searching very hard either. You could easily collect far more with a bit of application. The smaller ones benefit from a squint under the microscope, but even the larger ones are more interesting when viewed like that - you're welcome to bring yours in.

P.S. For some snail-related amusement I recommend a book I found recently: The Edible Mollusks of Great Britain and Ireland, with recipes for cooking them from 1867. The terrestrial snail recipes don't seem to have caught on in this country for some reason (mucilaginous broth, anyone?) but the book is padded out with meals made of marine molluscs, which for some reason the British seem relatively happy to eat. I'm not sure what the difference is really. This would seem to be a question for an anthropologist.

Some more spider resources

I was looking at the British Arachnological Society webpages today. They've got some friendly short leaflets about common spiders which you can download here. I thought they'd make useful reading for when you're just starting out on your arachnological journey.

They are producing a  WILDguide for British Spiders  which should be out relatively soon. I've got the equivalent book on British hoverflies and that's very good. Having been using the AIDGAP family key and the Collins guide,  I can see there's a gap for something else, so I'm looking forward to it.

I'm surprised that nobody's come in to use the microscopes yet to identify their spiders... perhaps you all have superhuman eyesight. Please do arrange to come in... the field centre is always open.

Spider webs on gorse. CC image by John Comloquoy.