Nannonyx, Lysianassa 37 



Head, lateral aiigles quadrate, slightly rounded. Side-plate 1 very 

 slightly expanded below, 4*'' greatly, the em argin ation stroiigly quadrate. 

 Pleon Segment 3, angles rounded. Antenna l, 2*^ and 3"^ joints short, 

 flagellum with 6 or 7 joints, accessory flagellum with 4 joints. Antenna 2, 

 ultiraate and penultimate joints of peduncle rather short, flagellum in 9 with 

 7 or 8 joints, in ö stout, with 18 short joints, most with calceoli. Mouth- 

 organs nearly as in N. thomsoni, but 2*^ Joint of mandible-palp not so long. 

 Maxilla 1, 2 very minute setae on inner plate. Terminal Joint of maxillipeds 

 showing no nail. Gnathopods 1 and 2, and peraeopod 3 nearly as in N. thomsoni. 

 Branchial vesicles almost simple. Uropod 3 very short, one brauch bluntly 

 conical, the other rudimentary. Telson as broad as long, sides slightly 

 converging, apex slightly concave. L. 3 — 4 mm. 



Southern Indian Ocean (Kerguelen Island). Rocky beaches. 



21. Gen. Lysianassa M.-E. 



1830 Lysianassa*) (part.), H. Milne Edwards in: Ann. Sei. nat., ^•. 20 p. 364 | 

 1840 Callisoma (nom. Jiud.), 0. Gr. Costa, Fauna Reg. Napoli, Crost., Cat. p. 5 | 1851 

 C. (non L. Agassiz 184H, (3oleoptera!) (part.), A. Costa, Fauna Reg. Napoli, läse. März. 

 1851 p. 1 I 1855 Lycianassa, T. Bell in: Reicher. Last Aret. Voy., v.2 p. 406 ] 1867 

 Subgen. Lysianassina, A.Costa in: Annuario 3Ius. Napoli, v.i p. 43 | 18SS Lysianax 

 (part.), T. Stebbing in: Rep. Voy. Cliallenger, v.29 p. 681. 1676. 



Body compressed. Side-plates large. Antenna 1, 2*^ joiut longer than 

 usual in this family. Antenna 2 short in 9, long in ö. Upper lip defined 

 by a uarrow incision and produced forward to a large linguiform plate. 

 Mandible slender, cutting edge simple, molar very small. palp attached 

 behind it, 1^* Joint not very short. ' Maxilla 1, inner plate without setae, 

 outer plate with crowded spines, palp cut into small teeth at apex. Maxilla 2, 

 inner plate much broader than outer. Maxillipeds, inner plates normal, outer 

 oval, without spines, minutely crenulate, palp long and slender. Gnathopod 1 

 simple. Gnathopod 2 subchelate or almost chelate. Peraeopods 1 — 5 rather 

 slender. Peraeopods 3 — 5, 2*^ Joint broadly expanded. Branchial vesicles 

 with accessory folds on one side only. Uropod 2, with one ramus con- 

 stricted. Uropod 3 not very small, rami narrowly lanceolate one-jointed, 

 setose only in d. Telson small, entire or minutely notched. 



7 species aceepted, 3 doubtful. 

 Synopsis of aceepted species: 



j Telson entire — 2. 



) Telson minutely notched — 6. 



j Pleon segment 3 uncinate 1. L. plumosa . . . p. 38 



\ Pleon segment 3 not uncinate — 3. 



j Telson apieally truneate — 4. __ 



\ Telson apieally rounded — 5. 



j Antenna 1, Ist Joint bidentate ' 2. L. bispinosa . . . p. 38 



\ Antenna 1, Ist joint smooth 3. L. cubensis . . . p. 38 



I Gnathopod 2 tendin^ to chelate 4L. longicornis . . p. 39 



) Gnathopod 2 simply subchelate 5. L. cinghalensis . p. 39 



j Peraeopod 3, 2d joint rounded 6. L. variegata . . . p. 39 



6 l Peraeopod 3, 2d joint narrow proximally, expanded 



\ distally 7. L. punctata . . . p. 40 



*) The name Lysianassa is n o t preoccupied by G. Münster (cfr. : 1846, Herrmannsen, 

 Ind. Gen. Malac., v.l p. 637). The Editor. 



