MARINE GAMMARIDEAOSr AMPHIPODA 313 



Maxillipedal palp 4-articulate, peduncle of uropod 3 short, subequal to 

 pleonite 6 and much shorter than peduncles of uropods 1-2 6 



6. Epistomal portion of prebuccal complex slightly produced, or flush, inner 



ramus of uropod 2 simple, inner ramus of uropod 3 half or less as long as 



outer ramus Nannonyx 



Labral portion of prebuccal complex acutely produced, inner ramus of 

 uropod 2 constricted, inner ramus of uropod 3 exceeding three fourths 

 length of outer ramus Paralysianopsis 



7. Inner ramus of uropod 2 constricted (fig. 131d) 8 



Inner ramus of uropod 2 simple 9 



8. Coxa 1 normally quadrate Pseudokoroga 



Coxa 1 tapering distally and partially hidden by coxa 2. 



"Orchomenella" groenlandica (Hansen) 



9. Article 1 of antenna 1 dorsodistally crested or toothed (fig. 124d), body 



often crested dorsally Lepidepecreum 



Article 1 of antenna 1 simple, body smooth or crested only on pleonite 4 . 10 



10. Article 3 of gnathopod 1 normally short and stout, articles 5 and 6 normally 



stout (fig. 12Qd) Orchomene 



Article 3 of gnathopod 1 elongate and slender like article 3 of gnathopod 2, 

 articles 5-6 elongate and slender (fig. 129i) Pseudorchomene 



11. Telson entire or emarginate 12 



Telson cleft one third or more 15 



12. Inner ramus of uropod 3 half or less length of outer . . . Parawaldeckia 

 Inner ramus of uropod 3 three fourths or more length of outer .... 13 



13. Upper hp prominently lobate, occasionally epistome also lobate (fig. 125c). 



Lysianassa, ?Socarnella, [Pronannonyx] 

 Upper lip not prominently lobate 14 



14. Telson distinctly longer than wide, inner ramus of uropod 2 constricted.' 



Parambasia 

 Telson not longer than wide, inner ramus of uropod 2 simple. 



Menigratopsis 



15. Article 2 of pereopod 3 deeply indentured (fig. 1316), article 3 of gnathopod 1 



elongate and slender like article 3 of gnathopod 2 Glycerina 



Article 2 of pereopod 3 with small teeth or none, article 3 of gnathopod 1 

 not elongate 16 



16. Coxa 1 tapering distally or shortened and partially hidden by coxa 2 



(fig. 1196) 17 



Coxa 1 large, subquadrate or scarcely tapering, mostly visible 18 



17. Palp article 2 of maxilliped half or less as broad as outer plate . . Ambasia 

 Palp article 2 of maxilliped as broad as or broader than outer plate. 



Ambasiella 



18. Inner ramus of uropod 2 constricted Socarnoides 



Inner ramus of uropod 2 simple 19 



19. Outer ramus of uropod 3 uniarticulate 20 



Outer ramus of uropod 3 biarticulate 21 



20. Palp article 2 of mandible about 3 times as long as article 1, article 3 two 



thirds length of article 2 Socarnopsis 



Palp article 2 of mandible about 5 times as long as article 1, article 3 about 

 half as long as article 2 Socarnella 



21. Gills strongly plaited (fig. 127s) Socarnes 



Gills minutely ridged or smooth 22 



22. Telson about as long as wide, cleft less than halfway, gills simple. 



Menigrates 



Telson about twice as long as wide, cleft more than halfway, some gills with 

 basal accessory lobes Waldeckia 



' Assumed in type-species. 



