Bate and Westwood, 1868
Head normally with a very short dorsal spine in the centre. All body segments, except segment 1 in male, with strong and numerous dorsal tubercles. These occur first on the posterior of segment 2 and become more numerous and pronounced on more posterior segments. Segments 1 and 2 elongate in male, each about twice the length of segment 3. Maximum length 15 mm in male and 10 mm in female.
Antenna 1 about half the body-length, flagellum of 11 to 13 articles. Antenna 2 little more than one-third of the length of antenna 1; flagellum with two articles, ventral surface with two parallel rows of long setae. Mandible without palp.
Gnathopod 2 inserted in the posterior half of the segment in male, in the anterior half in female; palm of the propodus in male with a large median protuberance bearing a small proximal tooth and a larger distal tooth; palm and outer edge often covered with fine setae. Female gnathopod 2 with palm of the propodus straight, with a proximal tooth and two rudimentary teeth.
Basis of pereiopods 5 to 7 with four tubercles; palm of the propodus with a proximal pair of grasping spines plus two or three pairs of short spines.
Abdomen with one pair of appendages and one pair of lobes in male, lobes only in female.
Anterior brood lamellae setose all round, posterior pair with only the posterior edges setose.
Sublittoral, often on buoys, flotsam and large hydroids.
North Sea, but scarce.