610 BULLETIN 159, UNITED STATES NATIONAL MUSEUM 



52. First 4 pairs of legs present and equally well developed 53 



First 4 pairs of legs present, but some of them rudimentary 62 



One or more pairs of legs entirely lacking 65 



53. Second antenna with a stout apical chela and no setae 54 



Second antenna with a single apical claw, and often setae 57 



Second antenna with setae only, no claw or chela 61 



54. Genital segment with laminate processes at its corners, extend- 



ing backward on each side of abdomen; leg rami 1-segmented; 



fins of fishes 9 Peniculisa Wilson, 1917 



Genital segment without processes; leg rami not 1-segmented 55 



55. Leg rami 3-segmented; first antenna 7-segmented; genital seg- 



ment cylindrical, longer than any thoracic segment 56 



Leg rami 2-segmented; first antenna 5-segmented; genital seg- 

 ment flattened and no longer than any of thoracic segments 

 preceding it; dredged, 360 fathoms 9 Pontopsyllus T. Scott, 1894 



56. Carapace with posterior and median lobes; between the two on 



either side a stout dorsal spine; a spine also inside each leg; 



gills of sharks cf 9 Krjz<yeria Beneden, 1853 (p. 452) 



Carapace without lobes, squarely truncated posteriorly; no 

 spines either on dorsal surface or inside base of each leg; 

 gills of sharks cf 9 Kr^yerina, new genus (p. 457) 



57. Legs all uniramose, 2-segmented, without setae, end segment 



with spines; first antennae 5-segmented; caudal rami lanceo- 

 late, without setae; gills of rays 9 Ergasilina Beneden, 1851 



Legs all biramose, armed with setae and not spines 58 



58. Rami of first 3 pairs of legs 2-segmented, of fourth pair 1-seg- 



mented; head and first segment fused, second and third seg- 

 ments free, fourth and fifth fused; giUs of eels. 



cf 9 Congericola Beneden, 1854 

 Rami of first 4 pairs of legs segmented alike; fourth segment 

 free, not fused :. 59 



59. All the rami 2-segmented; fifth legs uniramose, 2-segmented; 



maxillipeds verj' large and armed with powerful sickle-shaped 



apical claws; gills of sharks cf 9 Nemesis Risso, 1826 (p. 460) 



All the rami 3-segmented; fifth legs uniramose, 1-segmented; 

 maxillipeds turned forward and tipped with several curved 

 claws; gills of fishes cf Lernaea Linnaeus, 1758 



All the rami 3-segmented, often partly fused; fifth legs unira- 

 mose, 1-segmented; maxillipeds with chela or claw 60 



60. MaxiUipeds turned outward, their basal segments separated, 



each huge chela shutting horizontally; first antenna 5- to 

 7-segmented; gills of sharks cf 9 Eudactylina Beneden, 1853 (p. 466) 



Maxillipeds turned outward, but uncinate; first antenna 

 8-segmented, 2 basal segments enlarged with curved pos- 

 terior claws; gills of sharks. _ cf 9 Eudactylinodes, new genus (p. 468) 



Maxillipeds turned forward, their basal segments fused, each 

 with a simple apical claw shutting vertically; first antenna 

 1 1-segmented; gills of rays cf 9 Eudactylinella, new genus (p. 471) 



61. Leg rami 1- or 2-segmented; urosome as long as metasome; 



anterior thoracic segments shorter than the posterior; gills of 



fishes 9 Lamproglena Nordmann, 1832 



Leg rami 3-segmented; urosome shorter than the metasome; 

 anterior thoracic segments longer than the posterior; on an 

 annelid 9 Donusa Nordmann, 1864 



