The phylum Gastrotricha includes about 800 free-living species of microinvertebrates actively moving on and within sediment and vegetation in marine, brackish and fresh waters. Gastrotricha are part of the meiofaunal community that contributes to animal diversity and plays an ecological role in linking the microbial loop to the higher trophic levels of the aquatic environment.
This volume aims at giving a basic, up to date knowledge of the phylum with special reference to freshwater species (currently about 330). Synthetic diagnoses, drawings, and identification keys are provided for the species currently known in 4 out of the 5 families present in inland waters.