Nematoda (Eelworms)

These small unsegmented worms are very common in soil, water, silt and organic debris of caves, most of them are free-living. They are best seen under a microscope due to their small size. There are many species and identification is difficult - so there are certainly many new species to be found to add to cave species lists. Allolobophora chlorotica is responsible for worm casts in Otter Hole. Some are to be found deep in caves.

Annelida (Segmented worms)

These segmented worms (e.g. earthworm) are often abundant in caves, groundwaters and sediments living in soil. They ingest (‘eat’) mud and extract nutrients from it. All those found in caves also live in surface soils. Most of the time they will be hidden in soil and therefore hidden from view, so their importance underground could be underestimated. In sea caves sedentary polychaete (e.g. ragworms) worms are common.