COPEPODS OF THE WOODS HOLE EEGION 587 



35. Genital segment a little wider than long; fifth leg twice as long 



as wide, with a coarse inner spine and an outer seta at the 



tip; parasitic on Pecten 9 Pestalichomolgus, new name 2* 



Genital segment much longer than wide; fifth leg three times 

 as long as wide, with 2 equal filiform setae at its distal end; 

 in coelenterates 9 Paranthessius Glaus, 1889 



36. Metasome narrowed to a blunt point anteriorly and without 



chitin frontal lenses; second antenna with 2 curved apical 



claws and 3 setae; littoral, shallow water ? Lubbockia Glaus, 1863 



Metasome broadly rounded anteriorly, with a pair of large 

 chitin frontal lenses; second antenna with a single stout 

 apical claw; in tunicates- cT 9 Sapphirina J. V. Thompson, 1829 (p. 363) 



37. Second segment of second antenna with a row of 6 stout teeth 



on its inner surface, third segment with a curved claw, end 



segment with 3 claws; gills of Sabella 9 Sabelliphilus M. Sars, 1862 



Second segment of second antenna without teeth, third without 



a claw 38 



38. End segment of second antenna with a curved claw and short 



spine, subchelate; fifth body segment wider than fourth; 

 fifth leg with 2 equal setae; in a holothurian. 



9 Diogenidium G. L. Edwards, 1891 

 End segment of second antenna with 3 curved claws and 

 2 setae; fifth body segment narrower than the fourth; setae of 



fifth leg very unequal 39 



39- Gaudal setae no longer than last 2 segments of abdomen; fifth 

 leg twice as long as wide, with 2 setae; second segment of 

 fourth endopod with 1 seta; pallial cavity of mussels. 



c? 9 Modiolicola Aurivillius, 1883 

 Caudal setae longer than entire urosome; fifth leg four times as 

 long as wide, with 4 setae; second segment of fourth endopod 

 with 2 inner setae; in opisthobranch moUusks. 



c? 9 Anthessius Delia Valle, 1879 



40. Urosome 5-segmented in both sexes; genital segment much 



widened in female, with posterior spines in male; fifth leg 

 with 3 spines and 1 bristle; sponge and oyster washings. 



cf 9 Hersiliodes Ganu, 1888 

 Urosome 4-segmented in female, 5-segmented in male; genital 



segment scarcely widened in female, without spines in male 41 



41. Fourth segment of second antenna longer than third; anal 



segment of abdomen longer than preceding segment 42 



Fourth segment of second antenna shorter than third, or of 



equal length; anal segment shorter than preceding segment 44 



42. First antenna short and stout, 6-segmented, first segment with 



stout posterior spine; fifth leg 3, caudal rami 10 times as long 

 as wide; muddy bottom, 60 fathoms-- 9 Hippomolgus G. 0. Sars, 1917 

 First antenna slender, 9- or 17-segmented, no spine on first seg- 

 ment; fifth leg and caudal rami not as above 43 



43. Fifth leg and caudal rami as wide as long, the former with 1 



apical, 1 outer, and 1 inner seta; first antennae 9-segmented, 



short; muddy sand, 40 fathoms 9 Cyclopetta G. O. Sars, 1913 



Fifth leg and caudal rami nearly twice as long as wide, the 

 former with 1 apical, 1 outer seta, 1 inner spine; first antenna 

 17-segmented; fresh water 9 Macrocyclops Glaus, 1893 (p. 332) 



'* Pesta's name PseudolichomoJgus, 1909, was preoccupied in 1898 (see 77) . 



