Rostrum short, acutely pointed, reaching just beyond the eyes, dorsally provided with 4-6 small forwardly directed teeth.
Carapace not compressed; anterior part forms together with the rostrum a sort of hood projecting over the ocular region in part. A well marked groove runs from the orbital sinus down- and backwards.
Abdominal somites rounded above, without keels. Segment 6 little less than twice the length of segment 5.
Telson reaching beyond the exopod of the uropod; with dorsal sulcus, most narrow in the distal third, becoming broader again terminally. Apex rounded with 4-7 spines, dorsally with a few pairs of minute spines.
Antennular peduncle about 3/5 the length of the antennal scale.
Antennal scale rather less than half the length of the carapace, about three times as long as wide; outer margin practically straight, terminating in an apical spine.
Pereiopods 1-2 about equal in form and length; P3-5 not extremely long. Pereiopod 3 reaching beyond apex of antennal scale by the whole of the styliform dactylus; P4 almost of the same length as P3 and also with long dactylus. Pereiopod 5 without exopod and with extreme short dactylus.
Uropod with exopod 4.5 times longer than wide and longer than endopod.
Eyes small, opaquely whitely pigmented.
Life specimens are blood red coloured; ocular pigment opaque white
Up to 57 mm.
Mesopelagic, but also found in the top-hundred meters.
Distribution in the North Sea
Possibly northern North Sea.
H. glacialis is very closely related with H. gracilis and have been considered by several authors to be one species. According to Kemp the main difference is the presence of a groove on the carapace of H. glacialis. The rostrum is not (Sivertsen and Holthuis, 1956). May be infected with the rhizocephalan cirriped Trachelosaccus hymenodorae (G.O. Sars, 1879).
N Atlantic, also Arctic waters; from N Norway to Bay of Biscay, Faeroe Channel, off W reland; N Pacific Ocean
[After Kemp, 1910; Sivertsen and Holthuis, 1956]