CRUSTACEA MALACOSTRACA. III. 



129 



84. Echinozone arctica n. sp. 

 (PL XII, figs. 2 a— 2 c). 



Male (probably not full-grown). — Body nearly as slender as in Ilyarachna. Head broader than 

 the first but narrower than the second thoracic segment, with the surface smooth. — Basal joint of 

 the antennulse (fig. 2 b) very oblong, with the inner margin only a little less than twice as long as 

 the breadth of the joint; the outer margin somewhat convex without spines; the outer distal part 

 produced into an oblong process, which has a feathered seta but no spine on the obtuse end. — The 

 four proximal joints of the antennal peduncle constitute together a large body, much larger than in 

 any species of Ilyarachna or Echinozone seen by me, and as long as the sum of the head and the two 

 anterior thoracic segments; in all probability the two distal joints of the peduncle have been strong 

 and extremely long. — Mandibular palps seem to be entirely wanting; left mandible without movable 

 lacinia or setae. 



The four anterior thoracic segments without spines or crenulatiou on their front margin. The 

 specimen to hand shows the third segment conspicuously broader than the second, but whether this 

 may be quite normal is impossible to decide. Fifth segment considerably narrower and a good deal 

 shorter than the fourth; the posterior margin of both fifth and sixth segments very concave. The 

 three posterior segments with a conspicuous, rounded tubercle in the median line. — (All pairs of 

 thoracic legs have been well developed, but are lost, excepting their two proximal joints). 



Abdomen with a rounded tubercle in the median line somewhat from the base. — Uropods 

 (fig. 2 c) biramous; the endopod is somewhat robust; the exopod (ex) small but distinct. 



Length of the single male 2 - 2 mm. 



Remarks. In the large size of the proximal 4-jointed part of the antennce and to a lesser 

 degree in the shape of the basal joint of the antennulse E. arctica shows more affinity to Ilyarachna 

 Bergendali Ohlin than to any other species of the two genera in question. And therefore I think it 

 not improbable that /. Bergendali in reality ought to be referred to Echinozone. But as the differences 

 in the thoracic segments between /. Bergendali and E. arctica are so strong both as to shape — 

 especially of the fifth segment — and to armature, both must be valid species. 



Occurrence. Not taken by the "Ingolf". — The Ilnd Amdrup Expedition captured the single 

 male described at Jan Mayen, 55 fath. 



Group XI. Eurycopini. 



Body much varying in shape, rarely slender, generally moderately oblong or rather broad. 

 Head free, of moderate or very considerable breadth. Eyes wanting. Antennulse dorsal with first joint 

 plate-shaped, excepting in Syneurycope\ flagellum with several to numerous joints. Antennae somewhat 

 to very much longer than the body (in Syneurycope only the proximal part known), as the two distal 

 joints of the peduncle are considerably or extremely elongate, and the flagellum has numerous joints; 

 squama wanting or well developed. Mandibles most frequently mainly as in the Ianirini, but the molar 



The Ingolf-Expcdition. III. J. 17 



