Body short, narrowing sharply posteriorly. Very long appendages; antenna 2 subequal in length to the body, flagellum shorter than the peduncle. Eyes on lateral extensions of the head. Molar process of the mandible normal in structure, strongly developed with a truncate, denticulate grinding apex. Pereion segments 5 to 7 much smaller than segments 1 to 4 and sharply marked off from them; pereiopods relatively robust. Pleotelson with 2 to 6 large spines, visible from above on each lateral border, posterior border not serrated. Uropods small, lacking a peduncle, but with a distal, inward pointing, hooked process. Pleopod 1 of females absent, pleopod 2 forming a plate-like operculum; male pleopod 1 forming a copulatory preoperculum contributed to by pleopod 2.
Females up to about 3 mm long, males smaller, 1-7 mm.
Predominantly sublittoral, among sessile coelenterates, polyzoans, Laminaria holdfasts, etc., but also recorded at LWS.
Records are from Iceland, Norway and Scotland.