COPEPODS OF THE WOODS HOLE REGION 585 



17. Sucking tube short and enlarged into a disk at its tip; each fifth 



leg replaced by a single seta; head and caudal rami as wide as 



long; dredged, 1,000 fathoms 9 Pontoeciella Giesbrecht, 1895 



Sucking tube short, without a disk; fifth leg 2-segmented or 



lacking 18 



Sucking tube elongate, without a disk; fifth leg 1-segmented 19 



18. Head longer than wide; caudal rami four times as long as wide; 



fifth leg 2-segmented, its basal segment very short and fused 



with the body; dredged, 20 fathoms cf 9 Neopontius T. Scott, 1898 



Head much wider than long; caudal rami also wider than long; 

 fifth leg wholly lacking; genital segment inflated, deeply 

 cleft laterally; dredged, 385 meters 9 Dystrogus Giesbrecht, 1899 



19. Metasome segments without epimeral plates; caudal rami four 



times as long as wide; sucking tube reaching posterior margin 



of head; dredged, 40 fathoms c? 9 Myzopontius Giesbrecht, 1895 



Metasome segments with long, pointed epimeral plates; caudal 

 rami about as wide as long 20 



20. Posterior corners of bead conspicuously notched; epimeral 



plates pointed diagonally outward; genital segment about as 

 long as wide, dredged, moderate depths. 



9 Cribropontius Giesbrecht, 1899 



Posterior corners of head entire; epimeral plates curved back- 

 ward parallel with body axis; genital segment twice as wide 

 as long; dredged, moderate depths. _ 9 Sestropontius Giesbrecht, 1899 



21. Metasome little wider than urosome; rostrum lacking; basal 



segment of second antenna the longest, end segment with 6 

 curved apical setae; dredged, moderate depths. 



9 Pseudopsyllus T. Scott, 1902 



Metasome three times as wide as urosome; rostrum present; 



basal segment of second antenna the shortest 22 



22. Second antenna prehensile, with a stout apical claw; rostrum 



visible dorsally; end segment of first exopod with 4 spines, 



4 setae; dredged, 100 fathoms cf 9 Rhinomolgus G. 0. Sars, 1918 



Second antenna nonprehensile, with apical setae; rostrum not 

 visible dorsally; end segment of first exopod with 2 spines, 



6 setae; dredged, 20 fathoms 9 Hemicyclops Boeck, 1873 (p. 345) 



23. Fifth leg lacking, or replaced by 1 or 2 setae 24 



Fifth leg made up of a single distinct segment 31 



Fifth leg made up of 2 segments 46 



Fifth leg made up of 3 segments 55 



Fifth leg 4-segmented, distal segment with 4 subequal setae; 

 second antenna with 7 curved apical setae; caudal rami 



7 times as long as wide; dredged, moderate depths. 



c? Cyclopinodes, new genus (p. 319) 



24. Second antennae prehensile, with terminal claws 25 



Second antennae nonprehensile, with terminal setae 28 



25. Second antenna with 1 apical claw; first antenna 6-segmented 26 



Second antenna with 2 or 3 claws; first antenna with 8 or more 



segments 27 



