Gastrotrich

The gastrotrichs (from Greek γαστήρ, gaster, and θρίξ, thrix ), often called hairy backs, are a phylum of microscopic (0.06-3.0 mm) animals abundant in fresh water and marine environments. Most fresh water species are part of the periphyton and benthos. Marine species are found mostly interstitially in between sediment particles, while terrestrial species live in the water films around grains of soil.