Krøyer, 1855
Short generic diagnosis
Third maxillipede at most but little longer, sometimes shorter, than third pereiopod, its first joint rarely, the second-fourth joints never obviously incrassated in proportion to the joints in the third pereiopod; its two distal joints with numerous bristles along both margins. On the outer uropod the ciliated part never occupies half the exterior margin. The body not very long and slender, the distance between eyestalks and mandibles not very long. The first joint of the antennular peduncle considerably or much longer than third.
Description
Rostrum very short reaches only as far as the basal articulation of the eyestalks, a post-ocular spine present, gastro-hepatic groove well marked; second and especially third joint of antennular peduncle slender, antennal scale very strongly narrowed epically and more than three times as long as broad; fifth pereiopod less than half the length of the carapace (excluding rostrum); outer uropod five to five and a half times as long as broad.
Carapace laterally compressed and more than half the length of the abdomen, excluding the telson.
Eyes long and slender; the cornea is round and wider than the stalk. The corneal portion is not more than one third the length of the whole eye.
The basal segment of the antennular peduncle is long and considerably narrowed distally it is deeply hollowed for the reception of the eye. The ultimate segment is about five times as long as wide.
Scaphocerite is more than half the length of the carapace. It is rather less than four times as long as broad and is much narrowed distally.
First pair of pereiopods not chelate, reaches slightly beyond the middle of the antennular peduncle.
Second and third pairs possess a minute but perfectly formed chela.
Telson shorter than both uropods and is about two third the length of the sixth somite, sulcate above, with a pair of dorso-lateral carinae and a fringe of setae along its inferior margin.
Size
Length up to 65 mm.
Colour
The walls of the carapace are transparent, with a few small scarlet red chromatophores the black stomach and scarlet hepatic and cardiac regions show through very distinctly.
Ecology
Free-swimming, found at considerable depths.
Depth range
Adults live around 500 m depth, immature animals and larvae live in the surface layers t ca 100 m depth.
Distribution in the North Sea
Northern North Sea.
World distribution
E Atlantic Ocean south of Iceland and north of Scotland; Mediterranean; W Atlantic Ocean; also reported off S Africa, S America, Australia.
[After Kemp, 1910]