Halacarid mites
The Halacarid mites Synopsis covers the 66 species of Britain and Ireland.
Halacarid mites are minute arachnids. They live in marine, brackish and freshwater habitats throughout the world. Unlike the few insects and spiders which live in marine habitats but must breathe air, these mites can absorb oxygen from the water. This adaptation allows halacarid mites to live at great depths. So they range from intertidal habitats to 5000 metres down.
Scrapings of intertidal algae, hydroids, mussels and barnacles often yield large numbers of mites. Collect samples of substrate or washings from the substrate for lab analysis. Some of the freshwater species are abundant in wet Sphagnum moss. So if you tread down with a Wellington boot, the resulting free water can be sampled with a fine-meshed pond net. Other possible sources include fine debris from the bottom of lakes plus river bed gravel. Prepare specimens for examination under a light microscope.
Synopses of the British Fauna is a series of identification guides. Each volume in the series provides a detailed account of a group of animals. They bridge the gap between standard field guides and the more specialised monograph or treatise. Since 1993 the the Field Studies Council has published these guides on behalf of the Linnean Society.
These volumes are suitable for the lab or field. The editors aim to keep them as user friendly as possible. Technical terminology is kept to a minimum and a glossary of terms provided. However the complexity of the subject matter makes the books more suitable for the more experienced practitioner.