Lysianassidae 9 



often differentiated in d. Lower lip without inner lobes. Mandible (Fig. 2, 7, 8), 

 cutting edge almost simple (dentate in Valettia and Podoprion, wanting in 

 Kergueleuia, Fig. 2); accessory plate generally present on left mandible; 

 'molar seldom very robust; palp 3-jointed. Gnathopod 2 (Fig. 10, 11) usually 

 ^slender and delicate, 3*^ Joint elongate, 5*^ and 6*^ spinulose, 7*^ minute. 

 üropod 3 (Fig. 13) biramous (except in Acontiostoma and Stoma contion). 

 Hepato-pancreatic tubes (so far as known) 4. 



Marine. 



49 accepted and 2 doubtful genera, 136 accepted species and 35 doubtful. 



Synopsis of accepted genera: 



I Mandible (Fig. 2) without distinct cutting 

 edge 1. Gen. Kerguelenia . . . p. 11 

 Mandible (Fig. 7, 8) with distinct cutting 

 edge — 2. 



I Mouth-organs greatlyprojectingbelow, more 

 2 < or less stiliform — 3. 



l Mouth-organs not stiliform — 6. 



iEyes and gnathopod 1 (Fig. 3) powerfully 

 developed 2. Gen. Trlschizostoma . . p. 12 

 Eyes and gnathopod 1 not powerfully deve- 

 loped — 4. 



( Uropod 3 biramous 3. Gen. Acidostoma . . . p. 14 



)U ropod 3 not biramous — 5. 



f Uropod 3 without rami 4. Gen. Acontiostoma . . p. 15 



Uropod 3 with a single ramus 5. Gen. Stomacontion . . p. 16 



Eyes triple 



Eyes, when present, paired — 7. 



J Eyes triple 6. Gen. Hirondellea . . . p. 16 



j Gnathopod 1 chelate — 8. 



I 



Gnathopod 1 not chelate — 12. 



Maxilliped, palp 3-jointed; telson not cleft 7. Gen. Podoprionella . . p. 17 

 Maxilliped, palp 4-jointed; telson cleft — 0. 



r Peraeopod 3, 2d Joint deeply indentured . 8. Gen. Podoprion . . . . p. 18 

 9 i Peraeopod 3, 2d Joint not deeply in- 

 l dentured — 10. 



^ i Chela of gnathopod 1 narrow 9. Gen. Euonyx p. 19 



\ Chela of gnathopod 1 broad — 11. 



f Telson much longer than broad . . . . . 10. Gen. Opisa p. 20 



I Telson not much longer than broad ... 11. Gen. Sophrosyne . . . . p. 21 



^ J Mandible, cutting edge strongly dentate . 12. Gen. Valettia p. 22 



\ Mandible, cutting edge not strongly dentate — 13. 



..1 Maxilla 1 without palp 13. Gen. Amaryllis . . . . p. 23 



^ \ Maxilla 1 with 2-jointed palp — 14. 



< Mandible, molar rather strong; maxilliped, 

 1 4 ) P^lp rather long ; gnathopod 1 subchelate ; 



I telson entire or not deeply incised*) . 14. Gen. Onisimus . . . . p. 25 

 ^ These characters not combined — 15. 



*) Onisimus perplexes the arrangement by having the telson sometimes entire, 

 sometimes as deeply cleft as in Paratryphosites (p. 42). From the latter it is separated 

 by the much shorter outer plates of the maxillipeds. In Lysianassa (p. 37) the telson 

 sometimes has a small notch. 



