Haiice, Liljeboi'giidae 229 



coiisiderably beyond tlie otbers, subfoliaceous, inner margin setose, outer 

 ramus with small 2"^ Joint. Telson narrow, uuarmed, deeply cleft. 



1 species. 



1. H. abyssi Boeck 1871 H. a. -\- H. grandicornis (cj), A. Boeck in: Forh. 

 Selsk. Christian., 1870 p. 152, 153 | 1876 H. a., A. Boeck. Skand. Arkt. Amphip., v. 2 

 p.488 t.lO f. 2 I 1893 H.a., ö. 0. Sars, Crust. Norway, v.l p.412 1. 145 f. 2 | 1893 H.a., 

 A. DellaValle in: F. Fl. Neapel, «.20 p. 661 t. 59 f. 69— 71. 



Body moderately slender, peraeon in q mucb longer than in ö , pleon 

 Segments 4 and 5 produced to a dorsal acute subdeflexed tootb, larger in segment 5. 

 Head, rostrum nearly reacbing middle of 1^^ Joint of antenna 1, lateral corners 

 somewbat produced, narrowly rounded. Side-plate 1, front corners acutely 

 produced, 5*'^ more than twice as broad as deep, front lobe scarcely produced. 

 Pleon Segment 3, postero-lateral corners subquadrate. p]yes not represeuted 

 by auy trace of pigment. Antenna 1 in 9 , 1^*^ Joint nearly twice as long as 

 2'i and 3^^ combined, flagellum scarcely thrice as long as peduncle, 1^* Joint as 

 long as the next 8 combined; accessory flagellum nearly as long as peduncle, 

 with 3 joints, 1^* much the longest. Antenna 2 little longer, ultiraate Joint of 

 peduncle shorter than penultimate, flagellum subequal to the peduncle. In ö 

 antennae 1 and 2 nearly twice as long as in Q . Antenna 1, 1^* Joint 

 of flagellum exti-emely large, dense with sensory setae, about as long as 

 laminar accessory flagellum. Gnathopods 1 and 2, 5*^ Joint little expanded 

 distally, densely setose, 6*^ Joint much longer, rather narrow, bind margin 

 densely setose, flnger slender, smooth, a little curved. Peraeopods 1 and 2 

 scarcely longer than gnathopod 2, 4*^ Joint rather shorter than 5**^. Peraeo- 

 pods 3 — 5 long, slender; in peraeopod 3, 2*^ Joint rather small and narrow, 

 in 4*ii and 5*^ successively larger, 4*^ Joint considerably longer than 5^^ or 

 6*^, flnger short. Uropod 3, outer ramus rather longer than inner. Telsou 

 more than twice as long as broad, tapering, cleft nearly to base, apices 

 bidentate. Colour pellucid with faint yellowish tinge. L. 9 8, <3 ^ mm. 



Arctic Ocean, North-Atlantic, North-Sea and Skagerrak (whole Norway). Depth 

 188—752 m. 



18. Farn. Liljeborgiidae 



1899 Liljeborgiidae, T. Stebbing in: Ann. nat. Hist., ser. 7 i'. 4 p. 211. 



Pleon with one or more of the segments dorsally dentate. Head, 

 rostrum seldom large. Side-plate 1 produced forward, 4^^ emarginate behind. 

 Antenna 1 usually shorter than antenna 2, accessory flagellum well developed. 

 Upper lip slightly or not bilobed. Lower lip without-inner lobes. Mandible, 

 molar feeble. Maxillipeds, inner and outer plates rather small, palp elongate, 

 Gnathopods 1 and 2 strong. subchelate, gnathopod 2 the larger, often with sexual 

 Variation. Peraeopods 1 and 2 very slender. Peraeopods 3—5, 2^ Joint expanded, 

 5*^ pair the longest. Uropod 3, rami subequal in length. Telson cleft. 



Marine. 



2 genera, 10 accepted species and 2 doubtful. 



Sjraopsis of genera: 



Gnathopods 1 and 2, 5th Joint produced into a narrow lobe 1. Gen. Liljeborgia p. 230 

 Gnathopods 1 and 2, öt'i Joint little or not at all produced 2. Gen. Idunella . p. 234 



