COPEPODS OP THE WOODS HOLE REGION 593 



89. Fifth leg reduced to a tiny knob, without setae; second antenna 



with 2 apical, 1 lateral spines; metasome wider than long, 



depressed; pelagic, 470 fathoms cf 9 Metapontius Hensen, 1923 



Fifth leg distinctly 1-segmented, with 2 apical setae 90 



90. Second antenna with 2 to 4 claws and 1 or 2 setae on end 



segment; first antenna 7-segmented; end segment of third 

 exopod shorter than other two; in compound ascidians. 



c? ? Lichomolgus (part) Thorell, 1860 

 Second antenna with 6 or 7 setae and no claws on end segment; 

 first antenna 6-segmented; end segment of third exopod as 

 long as other 2 combined; marine, littoral ? Onceola Kramer, 1895 



91. Second antenna with 1 stout apical claw; metasome segments 



with broad epimeral plates; fifth leg 1-segmented, with 2 

 apical setae; invertebrate washings. 



cf 9 Paralichomolgus Thompson and Scott, 1903 

 Second antenna with 7 apical setae; metasome segments without 

 epimeral plates; fifth leg 3-segmented, end segment with 4 

 setae; muddy sand, 30 fathoms cT 9 Pterinopsyllus Brady, 1880 



92. Metasome wider than long, with lateral epimeral plates; second 



antenna 3-segmented, with 1 apical claw; fifth leg 1-seg- 

 mented, with 2 setae; parasitic on Linkia. 



c^ 9 Linkiomolgus Stebbing, 1900 

 Metasome much longer than wide, without epimeral plates 93 



93. Fifth leg six times as long as wide, curved; second antenna with 



6 apical setae and sometimes a large claw, toothed on the 



inside; littoral, among algae cf 9 Macrocheiron Brady, 1872 (p. 348) 



Fifth leg twice as long as wide, straight; second antenna with 

 2 or 3 apical claws, none of them toothed, and 2 or 3 setae; 

 in ascidians cT 9 Lichomolgus (part) Thorell, 1860 



94. Forehead without chitin eye lenses 95 



Forehead with a pair of large chitin eye lenses 97 



95. Fourth endopod three to five, caudal rami two or three times 



as long as wide 96 



Fourth endopod not twice as long as wide; caudal rami as wide 

 as long; fifth leg 1-segmented, with 2 tiny equal apical setae; 

 dredged, 20 fathoms 9 lichomolgella G. O. Sars, 1918 



96. Fifth leg a rounded knob, with 1 spine and 2 filiform setae; 



fourth endopod with 2 apical setae only; first endopod un- 

 modified in male; parasitic on echinids. 



cf 9 Pseudanthessius Glaus, 1889 

 Fifth leg a flattened lamina, with 3 spines; fourth endopod 

 with 2 apical and 1 inner setae; first endopod much modified 

 in male; littoral, free swimming cT 9 Kelleria Gurney, 1927 



97. Head squarely truncated anteriorly; second antenna 4-seg- 



mented, slender; fourth metasome segment without processes; 

 caudal rami long, divergent; pelagic, at surface. 



cf 9 Copilia Dana, 1849 (p. 374) 

 Head rounded anteriorly; second antenna 3-segmented, stout; 

 fourth metasome segment with sharp processes at posterior 

 corners; caudal rami shorter; pelagic, at surface. 



cf 9 Corycaeus Dana, 1845 (p. 354) 



