Pleon segment 4 in female depressed dorsally with pair of anteriorly directed setae and pair of short posteriorly directed spines; in male depression deep and setae very long and curved. Coxal plate 1 apex narrowly rounded, posterior margin smooth, posterodistal margin with 1 long seta; coxal plates 2 and 3 posterodistal angle narrowly rounded, but may be quadrate or with small notch and inset short seta, distal margin with about 7 or 8 setae in female, 5 or 6 in male. Epimeral plate 3 posterodistal angle with prominent tooth in small females, tooth becoming less conspicuous or absent in large females, in small males the margin is weakly angular and in large males broadly rounded; epimeral plate 3 distal margin with one spine group. Eyes oval. Antenna 1 peduncle article 1 with apex evenly rounded, ventral margin with 1 plumose seta, flagellum in female 5 to 6-articulate, in male 7 to 8-articulate. Antenna 2 flagellum 5-articulate in female, in male filiform and greatly exceeding length of body.
Up to 3 mm.
Depth range from the intertidal to about 10 metres.
English Channel, Yorkshire, Ireland.