MARINE GAMMARIDEAN AMPHIPODA 235 



10. Maxilla 2, medial edge of inner plate lined with setae (fig. 95g), article 2 of 



outer ramus of uropod 3 subequal to article 1 in length (fig. 96/) . Eriopisa 



Maxilla 2, medial edge of inner plate unarmed, article 2 of outer ramus of 



uropod 3 much shorter than article 1 or absent 11 



11. Outer ramus of uropod 3 biarticulate Eriopisella 



Outer ramus of uropod 3 uniarticulate Netamelita 



12. Rami of uropod 3 foliaceous, oval, apically rounded (fig. 96e) , either coxa 2 



or 3 much shorter than coxa 1 Megaluropus 



Rami of uropod 3 lanceolate, or apices truncate (figs. 9Qb,d), not foliaceous, 

 coxae 2-3 as long as coxa 1 13 



13. Mandibular palp article 2 shorter than article 1 Parelasmopus 



Mandibular palp article 2 equal to or longer than article 1 14 



14. Gnathopod 1 subchelate 15 



Gnathopod 1 simple (fig. 95j) 17 



15. Inner plate of maxilla 1 poorly setose (2-5 setae) Elasmopus 



Inner plate of maxilla 1 densely setose (11 setae) 16 



16. Uropod 3 strongly exceeding uropod 1, outer ramus 2-articulate. 



Liagoceradocus 

 Uropod 3 not exceeding uropod 1, outer ramus 1-articulate . Anelasmopus ^ 



17. Female gnathopod 2 simple (fig. 95Z) Cheirocratus 



Female gnathopod 2 subchelate 18 



18. Antenna 1 nearly as long as antenna 2 Cheirocratella 



Antenna 1 reaching only to end of peduncle of antenna 2 Casco 



19. All pereonites carinate Gammaracanthus 



Pereonites not carinate, or occasionally numbers 6-7 are carinate ... 20 



20. Urosome with two or three segments bearing bundles or rows of articulate 



spines 21 



Urosome occasionally with scattered spines not on all segments and not ar- 

 ranged in bundles, spines usually absent 26 



21. Some segments anterior to pleonite 4 bearing dorsal articulate spines. 



"echinogammarus" members of Anisogammarus 

 No segments anterior to pleonite 4 bearing dorsal articulate spines (oc- 

 casionally bearing teeth or serrations) 22 



22. Metasome with posterodorsal teeth and/or serrations 23 



Metasome lacking posterodorsal teeth and serrations 25 



23. Telsonic apices quadrate, lobes closely appressed and separated by a slit. 



Maerella 

 Telsonic apices subacute, lobes gaping 24 



24. Metasomites with a single dorsoposterior tooth. 



"Marine Carinate Gammarus" 

 Metasomites multiserrate dorsoposteriorly Mesogammarus 



25. Gnathopod 1 slightly larger than 2, both gnathopodal palms bearing two or 



more chisel-shaped spines in rows Anisogammarus 



Gnathopod 1 smaller than or equal to 2, palms bearing one or no chisel- 

 shaped spines Gammarus 



26. Inner ramus of uropod 3 scale-like, very small (fig. 96/) 27 



Inner ramus of uropod 3 nearly as long as outer 28 



27. Uropod 3 strongly exceeding apex of uropod 1 Melita 



Uropod 3 not exceeding apex of uropod 1 Melitoides 



28. Rami of viropod 3 foliaceous, oval, apices rounded (fig. 96e) 29 



Rami of uropod 3 lanceolate, square, or apices truncate or pointed ... 30 



-' Not clearly described. See diagnoses. Hornellia Walker re='embles Anelasmopus but the inner plate of 

 maxilla 1 has not been described. 



285-135 O - 69 - 16 



