Guide to Leeches?

[Yashca]

Is there a book or key specifically for the UK leech species?

I don't know how many leech species there are, but I find them every now and then when I am pond dipping, and I've only ever managed to identify one to species level.

[Richard Baber]

There's an old guide, published half a century ago, called "A Key to the British Leeches with Notes on Their Ecology". There are a few secondhand copies on offer in the UK Amazon Marketplace at the moment:
A Key To The British Freshwater Leeches with notes on their Ecology: Amazon.co.uk: K.H. & Watson, E.V Mann: Books

I believe that there are around 16 UK species, though I could be very wrong. There's a basic online guide to some of them at:
Leeches, Hirudinea

Richard

[Yashca]

That's excellent Richard, thank you.

[rautospoon]

This is the latest publication, which is still available from the Freshwater Biological Asociation:

Scientific Publication 40. Leeches .................... £14.00
A Key to the British Freshwater Leeches, with Notes on their Life Cycles and Ecology
J.M. Elliott & K.H. Mann
1979 (reprinted 1998), 72pp.
ISBN 978-0900386-38-1

Cheers.