Urosome segments fused; without lateral ridge, uropods inserted laterally. Head with small triangular rostrum, lateral lobes weakly produced in female, more prolonged in male. Female antenna 1 peduncle article 1 ventral margin with 5 or 6 long spines, proximal spine curved, inner margin with 3 or 4 short proximal spines and several long distal setae. Male antenna 1 peduncle article 1 ventral margin with 3 short spines, inner margin without spines or setae. Female antenna 2 peduncle article 4 with few long setae, inner ventral margin with 3 or 4 pairs of spines, article 5 moderately setose, setae long, inner distal margin not produced, ventral margin with 1 to 3 long spines but no process. Male antenna 2 peduncle article 4 sparsely setose, distal ventrolateral angle with 1 large and 2 small acute processes, inner ventral margin without spines, article 5 sparsely setose, setae short, inner distal margin produced, ventral margin without spines but with single proximal process. Gnathopod 1 palm oblique, convex. Uropod 1 peduncle outer margin with 6 or 7 spines, inner margin with 3 to 5 spines; uropod 2 peduncle dorsal surface with 1 to 3 spines.
Up to 5 mm.
Constructs tubes on algae, hydroids and other organisms, in shallow subtidal habitats of reduced salinity, often in sheltered harbours and estuaries. Frequently found on buoys and rafts, or in the galleries made by the wood-boring isopod Limnoria .
Cosmopolitan in temperate and tropical coastal regions; North Atlantic, American and European coasts; North Sea; Mediterranean; Black Sea; Indian Ocean, south and east Africa, Sri Lanka; Pacific Ocean, Australia, New Zealand, Japan, China; west coast of North America.