412 PROCEEDINGS OF THE ACADEMY OP [1879. 



o Genus Pontophilus Leach, Sars. 1 Rostrum short, eyes free; 

 antennulse' biflagellate; first pair of pereiopoda stout, second pair 

 very short, slender, chelate. Branchiae seven, including a rudi- 

 mentary one on the second maxillipeds. T} r pe Pontophilus sjn- 

 nosus Leach. 



o Genus Sabinea Owen. 2 Rostrum very short, eyes free, stout ; 

 second pair of pereiopoda very short, not chelate, dactylus minute. 

 Branchioe as in Pontophilus. 



o Genus Nectocrangon Brandt. 3 Rostrum wanting ; eyes nearty 

 hidden by the carapax ; second pair of pereiopoda chelate; dac- 

 tyli of fourth and fifth pairs dilated, natatorial. Branchiae five 

 on each side, none on the second maxilliped. Type Nectocrangon 

 lar (Owen sp.). 



o Genus Paracrangon Dana. 4 Rostrum elongate, eyes free; 

 second pair of pereiopoda obsolete, fourth and fifth pairs acuminate 

 gressorial. Type Paracrangon echinatus Dana. 



Sub-Family Lysmatinae. 



First pair of pereiopoda stouter than the second, both pairs 

 chelate, fingers subequal, carpus of the second pair annulate. 

 External maxillipeds pediform. 



o Genus Nika Risso. 5 Rostrum short, antennulse biflagellate 

 Hands of first pair of pereiopoda dissimilar, one being chelate, 

 the other not; carpus of second pair elongate, multiarticulate ; 

 hand minutely chelate. Type Nika edulis Risso. 



o Genus Lysmata Risso. 6 Rostrum elongate, sub-ensiform, 

 dentate; antennulse triflagellate ; first pair of pereiopoda stout, 

 of medium length, chelate; second pair elongate, carpus multi- 

 articulate; hand rudimentary. Type Lysmata seticauda Risso. 



Genus Hippolysmata Stm. 7 Rostrum elongate, antennulse 

 biflagellate. External maxilliped elongate, furnished with exog- 



1 Forkandlingar i Vedenskabs Selskabet i Christiania, 1861, f. 183. In- 

 cluding ^Egeon Risso. 



' l Appendix to the voyage of Captain Ross, p. 82 (1835). 



3 Argis Kroyer Naturhistorisk Tidsskrift. iv. p. 267 (1842-3) (nom. 

 prseoc.). Nectocrangon Brandt, in Middendorff's Reise in den Ausserten 

 Norden und Osten Siberiens, Band II. Zoologie, Theil 1. p. 114 (1851). 



4 U. S. Exploring Expedition, Crustacea, p. 537. 



6 Processa Leach. 6 Melicerta Risso. 



Proc. Phila. Acad., 1860, p. 26. 



