Introduction
The hypogean (subterranean) Crustacea recording scheme is a small scheme dealing with the subterranean macro-Crustacea found in the groundwater and aquatic cave habitats of the British Isles, including Ireland. The scheme only encompasses the larger Crustacea specifically evolved to exist in underground aquatic habitats (stygobites). Adaptations to the underground aquatic environment typically involve a lack of pigment (i.e. specimens are white in colour), a lack of eyes and over-development of antennae and legs. Most species are also very small and have a thin body shape for squeezing between small water-filled crevices in underground rock strata and water-logged gravels.
