Jlhachotropis 361 



Body thick, broad, peraeon unarmed, except for dorsal denticle on 

 Segment 7, which has the bind corners acute, pleon segments 1 — 3 tricarinate, 

 teetb acute, except dorsal tootb on segment 3, wbicb is subacute. Head, rostrum 

 ratber small, lateral corners little produced, sligbtly rounded. Side-plate 1 

 nearly twice as broad as deep. Pleon segment 3, postero-lateral margin 

 firmly serrate. Eyes very large, triangulär, occupying major paii of bead's 

 ' surface, nearly meeting at top, black. Antenna 1, 1^* Joint very stout, not 

 very long, but as long as 2*^ and 3*^ combiued, 3*1 very sbort, flagellum 

 ratber longer tban peduncle, 23-jointed; accessory flagellum apparently 

 wantiug. Antenna 2 subequal to antenna 1, flagellum ratber sborter tban 

 peduncle. Gnatbopods 1 and 2, 6*^ Joint large. broadly oval, defining tootb 

 of palm not very prominent. Peraeopods 1 — 5 long, slender, successively 

 longer. Peraeopods 3 — 5, 2^ Joint piriform, very small in peraeopods 3 

 and 4. much larger but still small in peraeopod 5. Telson more tban twice 

 as long as broad, tapering to tbe acute, little separated apices, cleft - ^ of 

 lengtb. L. 9 9'5, ö 11-5 mm. 



Arctic Ocean (Greenland). Depth 19 — 81 m. 



«. R. inflata (0. Sars) 1882 Tritropis i., G. 0. Sars in: Forh. Selsk. Christian., 

 nr. 18 p. 104 t. 5 f . 7 [ 1888 RJiachoiropis i., T. Stebbing in: Rep. Voy. Challenger, u 29 

 p. 540 I 1893 & 95 R tümida, R. l, G. 0. Sars, Crust. Norway, ».1 p.'430 t. 152; p. 697 ] 

 1893 Pontogeneia aculeata (part.)?, A. Della Valle in: F. Fl. Neapel, u 20 p. 617. 



Body ratber sbort, peraeon mucb iuflated, dorsally smootb, pleon 

 Segments 1—3 tricarinate, carinae produced into small teetb, except central 

 of segment 3, segments 4 — 6 quite smootb. Head very broad, rostrum 

 ratber prominent, lateral corners linguiform, sligbtly deflexed. Side- 

 plates nearly as in K. belleri. Pleon segment 3, postero-lateral margins 

 strongly seiTate, serration turning tbe corner. Eyes very large, convex, 

 rounded oval, or reniform, dark brown. Antenna 1 in p sbort, witbout 

 distinct calceoli, 1^* Joint longer tban 2*^, 3^ scarcely balf as long as 2*, 

 flagellum longer tban peduncle. 9-jointed; accessory flagellum 2-jointed. 

 Antenna 2 in 9 little longer, ultimate and penultimate joints of peduncle subequal, 

 flagellum balf as long as peduncle, 8- or 9-jointed. Antennae l and 2in d mucb 

 longer; antenna 1, flagellum witb 12 joints, 1^* very long, densely clotbed 

 with sensory setae. Gnatbopod 1, 6*'' Joint oval, breadtb mucb more tban 

 balf lengtb; gnatbopod 2, 6*^^ Joint twice as long as broad; in botb tbe 

 palm evenly curved, defined by sligbt angle carrying 1 spinule, fiiii;e;- long, 

 curved. Peraeopods 1 — 5 slender. of moderate lengtb, 2^ Joint in pöraeo- 

 pod 3 very sligbtly expanded, in peraeopod 5 mucb broader, narrowing 

 distally. Uropods 1 — 3, outer ramus notably sborter tban inner, rami of 

 uropod 3 narrowly lanceolate. Telson less elongate tban usual, carrying a 

 large sensory setule above tbe middle on eacb side, tbence rapidly tapering 

 to tbe acute contiguous apices, cleft almost to tbe centi'e. Colour generally 

 variegated witb patcbes of carmine and specks of golden yellow, antennae 1 

 and 2 and limbs banded. L. 9 scarcely more tban 6 mm, ö somewbat less. 



Arctic Ocean, North-Atlantic, North-Sea and Skagerrak (Greenland; Kara Sea; 

 Norway, depth 19—94 m). 



7. R. helleri (Boeck) 1871 Trüropis h., A. Boeck in: Forh, Selsk. Christian., 

 1870 p. 159 I 1876 T. k, A. Boeck, Skand. Arkt. Amphip., v.2 p. 513 t. 20 f. 6 | 1893 

 Rhachotropis h., G. 0. Sars, Crust. Norway, v.l p.426 1. 150 | 1888 R. aculeatus (part.), 

 T. Stebbing in ; Rep. Voy. Challenger, v. 29 p. 954 ] 1893 Pontogeneia aculeata (part.), 

 A. Della Valle in: F. Fl. Neapel, u20 p. 616. 



