498 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 117 



15. Palm of gnathopocl 2 bearing defining tooth 16 



Palm of gnathopocl 2 lacking defining tooth 21 



IG. Gnathopod 2 with teeth besides defining one 17 



Gnathopod 2 only with defining tooth E. minimus 



17. Palm of male gnathopod 2 bearing 2 teeth E. delaplata (in part) 



Palm of male gnathopod 2 bearing 3 or more teeth 18 



18. Palmar hinge tooth of male gnathopod 2 armed with spines 19 



Palmar hinge tooth of male gnathopod 2 not armed with spines. 



E. calliactis 



19. Middle palmar tooth of male gnathopod 2 broadly and asymmetrically 



subconical E. holgurus 



Middle palmar tooth of male gnathopod 2 narrowly conical or columnar . . 20 



20. Article 2 of pereopods 3-5 bearing long setae behind, accessory flagellum 2 



or more articulate E. rapax 



Article 2 of pereopods 3-5 lacking long setae behind, accessory flagellum 

 uni-articulate E. rapax mutatus 



21. Dactyli of pereopods bearing lines of small erect, blunt teeth. 



E. spinidactylus 

 Dactyli of pereopods smooth or bearing articulated setae 22 



22. Apices of telson broadly rounded, not spinose E. afBnis 



Apices of telson subacute, truncate, notched, convex and/or spinose ... 23 



23. Article 2 of pereopod 4 with a fluted and crenulated posterodistal excavation. 



E. pecteiiicrus 

 Article 2 of pereopod 4 oval, serrate normally 24 



24. Palm of gnathopod 2 heavily setose 25 



Palm of gnathopod 2 not heavily setose 29 



25. Third plconal epimeron quadrate behind 26 



Third pleonal epimeron with a small posterodistal tooth 27 



26. Pereopod 5, anterior edge of article 4 produced downward . E. ecuadorensis 

 Pereopod 5, anterior edge of article 4 not produced E. perditus 



27. Pereopod 5, anterior edge of article 4 produced downward strongly. 



E. delaplata (in part) 

 Pereopod 5, anterior edge of article 4 not produced downward 28 



28. Gnathopod 2, process near finger hinge bearing stout spines . . E. biichneri 

 Gnathopod 2, process near finger hinge lacking stout spines . E. antennatus 



29. Palm of gnathopod 2 with 3 processes E. erythraeus 



Palm of gnathopod 2 with 2 processes E. pseudaffinis 



Palm of gnathopod 2 with one process 30 



30. Palm of gnathopod 2 lined with stout spines its full length . . E. spinimtanus 

 Palm of gnathopod 2 lacking spines or with spines restricted to a group . .31 



31. Gnathopod 2, middle of palm with rod-like process E. excavatus 



Gnathopod 2, palm bearing only a short, broad process near hinge. 



E. fusimanus 



Elasmopus atolgidus, new species 



Figure 10 



Diagnosis of female: Eyes large, black ; accessory flagellum composed 

 of two articles tipped with a minute third; pereopods 1-2 bearing 2 

 large curved distal spines on sixth articles, article 7 with distal claw 

 scarcely distinct, but bearing 3 minute setules; posterior edge of tliird 

 pleonal epimeron slightly convex, lower corner rounded, except for 



