248 Halicreion, Arrhis 



pod 5, very long, 2*^ Joint piriform, 4^^^ rather shorter than 5^'^, 5*^ tban eitlier 6*^^ 

 or finger. üropods 1 and 2 scarcely reaching beyond peduncle of uropod 3. 

 üropod 3, rami narrow, lanceolate, unarmed, louger than the long peduncle. 

 Telson scarcely longer than broad, apical margin slightly concave. Coloiir 

 whitish tinged with yellow. L. 9 5, d 4 mm. 



North- Atlantic, Xorth-Sea and Christiauiafjord (Norway, depth 94 — 188 m; 

 St. Magnus Bay [Shetland Islands], depth 55 — 110 m). • 



9. Gen. Arrhis Stebb.*) 



1861 Aceros (Sp. typ.: Oedicerus obtusus) (non C. L. Eonaparte 1850, AvosI), 

 A. Boeck in: Forh. Skand. Naturf., Mede 8 p. 651 | 187]r A., A. Boeck in: Forh. Selsk. 

 Christian., 1870 p. 172 ] 1892 A., G. 0. Sars, Crust. Norway, v. 1 p. 338. 



Body slender. Head without fi'ontal process. Side-plates not deep, 

 1^* produced forward. Eyes inconspicuous, their pigment patches not con- 

 tiguous. Antenna 1 in 9 longer than antenna 2, or as long, peduncle very long, 

 much longer than in antenna 2, flagellum short. Lower lip, inner lobes separate. 

 Mandible strong, cutting edge little dentate, molar strong, 2^ Joint of palp 

 arcuate. .Maxilla 1, outer plate with 7 spines (Schneider). Maxillipeds, inner 

 plates not reaching apex of 1^* Joint of palp, outer not nearly reaching apex 

 of the distally widened 2^ Joint. Gnathopods 1 and 2, 5*'^ Joint long, produced 

 to narrow setose process, 6*^^ oval, palm oblique, pretty well defined. Peraeo- 

 pods 1 and 2 rather longer than peraeopods 3 and 4, finger in all lanceolate. 

 Peraeopod 5, uropods 1 — 3 and telson not generically distinctive. 



1 species. 



1. A. phyllonyx (Sars) 1858 Leucothoe p.. M. Sars in: Forh. Selsk. Christian., 

 p. 148 I 1862 Montagua p., Bäte, Cat. Auiphip. Brit, Mus., p. 369 ] 1871 Aceros p., 

 A. Boeck in: Forh. Selsk. Christian., 1870 p. 172 | 1887 A. p., H.J.Hansen in: Vid. 

 Meddel., ser. 4 v.9 p. 117 t. 4 f. 7 [ 1892 A. p., G. ü. Sars, Crust. Norway, v.l p. 338 

 t.ll9; t.l20 f.l I 1893 Halimedonp., A. Della Valle in: F. Fl. Neapel, r.20 p.535 t. 58 

 f. 23 — 27 I 1859 Oediceros obtusus, R. M. Bruzelius in: Svenska Ak. Handl., n. ser. v.3 

 nr. 1 p. 92 t. 4 f. 17 | 1861 Oedicerus o., Aceros sp. typ., A. Boeck in: Forh. Skand. 

 Naturf., Mede 8 p. 651. 



Tumid anteriorly. Head tumid with swollen cheeks, front truncate. 

 Side-plate 1 produced aloug lower side margins of head, 3^ with insinuate 

 lower margin, 5*^, 6^^ and 7**^ unusually broad. Eyes separate, on sides of head 

 near the front, represented by 2 small patches of whitish pigment. Antenna 1 in 5 , 

 2<^ Joint nearly twice as long as l^S setose on both edges, flagellum very 

 Short, 11-jointed, in (young) ö somewhat longer. Antenna 2, ultimate and 

 penultimate joints of peduncle subequal, and together as long as flagellum 

 in o, flagellum longer in ö. Gnathopod 1, S*'^ Joint longer than G*'\ its 

 setose process not lying near hind margin of 6^^, palm longer than the 

 bind margin. Gnathopod 2 nearly resembling gnathopod 1, but longer. and 

 process of 5*'^ Joint narrow, lying near margin of 6*'\ Peraeopods 1 and 2, 

 2^ Joint bent, 4*^ large, very setose, 5^^' and 6^^ equal, finger shorter, compressed, 

 lanceolate. Peraeopods 3 and 4, 2*^ Joint long oval, finger as long as e*^'^ Joint. 

 Peraeopod 5 elongate, 2'^ Joint large, elongate piriform, 5*^ Joint shorter than 

 4*'\ much shorter than 6*^^. Uropods 1 and 2, rami densely spinöse, uropod 3, 



*) Nom. nov. ctfi^K;, without nose. — The nanie Aceros is preoccupied (1850, 

 C. L. Bonaparte, Consp. Av., v. 1 p. 90). 



