CRUSTACEA MALACOSTRACA. III. 83 



and sixth joint twice, as long as the fourth; seventh joint is a little more than half as long as the 

 fourth and shorter than the claw. Seventh pair (fig. 6 e), and especially almost their distal half, very 

 slender; second joint with a row of very fine and somewhat short setae along the proximal half of 

 the posterior margin, while the anterior margin has only about four setae; third joint is slightly longer 

 than the second; fifth joint is somewhat more than twice as long as the fourth but even slightly 

 shorter than the sixth, which is extremely long; seventh joint nearly as long as the fourth, extremely 

 slender, and a little longer than the setiform claw. 



Abdomen conspicuously shorter than the two posterior segments combined (fig. 6 f), somewhat 

 less than twice as long as broad, considerably tapering towards the base and again narrowing before 

 the postero-lateral parts, each of which is somewhat produced outwards as a triangle; the hind margin 

 is unusually long, conspicuously longer than the basal breadth of the abdomen, and only moderately 

 convex, slightly concave near the insertions of the uropods. — The operculum (fig. 6 g) occupies about 

 three-fourths of the length of the ventral excavation; its parts differ considerably from those in M. 

 spinifera or M. abyssicola, but as they seem to be somewhat deranged in the specimen, I have figured 

 them as well as possible without removing them from the animal, and omit a description. The anal 

 doors are short, and situated considerably behind the operculum close at the end of abdomen. — (The 

 uropods are lost). 



Length 2-9 mm. 



Remarks. M. longipes is distinguished from the other species by the enormous length of 

 seventh pair of legs, as I suppose that the unknown female agrees with the male in this feature. In 

 the antennulae and the shape of the three posterior thoracic segments this male differs considerably 

 from the same sex of the preceding forms. 



Occurrence. Taken by the "Ingolf" at a single station in the cold area. 



East of Iceland: Stat. 102: Lat. 66°23' N., Long. io°26' W., 750 fath., temp. -=-0-9°; 1 spec. 



Group VIII. Nannoniscini. 



Bod} oblong, considerably depressed, with the sides expanded. Head free; eyes wanting. An- 

 tennulae dorsal, short, with very few joints in the flagellum. Antennae well developed; squama distinct. 

 — Mandibles 'with the incisive part, the movable lacinia, and the setae well developed; the molar 

 process tapers strongly to the narrow, obtuse, setiferous end, and is directed somewhat backwards ; 

 palp 3-jointed. Palp of the maxillipeds with second joint much expanded and the two distal joints 

 small; epipod very long. — Thoracic segments movable, excepting that sixth and seventh segments 

 are generally fused at the middle. The thoracic legs inserted on the ventral side; first pair rarely 

 really prehensile, generally simple; the six other pairs without processes from first joint, adapted for 

 walking, and sometimes the three posterior pairs have, besides, natatory setae on fifth and sixth joints, 

 furthermore they are moderately slender and not differiug much in length; an accessory claw frequently 

 distinct. — Abdomen at most with a vestige of a basal segment; uropods ventral, somewhat small 

 biramous, with unjointed rami. 



