COPEPODS OF THE WOODS HOLE REGION 589 



51. End segment of fifth leg obtusely truncated, with lanceolate 



spines at corners, between them a filiform seta; first antennae 



10-segmented; marine, littoral c? 9 Cyclopina Claus, 1863 (p. 317) 



End segment of fifth leg 3-lobed, each lobe with a plumose 

 seta; metasome tumid and boldly vaulted; first antennae 

 17-segmented; fresh water, everywhere. 



c^ ? Macrocyclops Claus, 1893 (p. 332) 



52. Caudal rami seven or eight times as long as wide; end segment 



of fifth leg bluntly rounded, with 2 apical and 2 outer setae, 



all 4 equal; littoral, among algae cT 9 Qiardella Canu, 1888 



Caudal rami much shorter, except in one species of Euryte 53 



53. Body cylindrical, metasome segments only slightly narrowed 



posteriorly; first antenna 6-segmented, second pair with 2 

 apical claws, 3 setae; mantle cavity of clams. 



9 Myicola Wright, 1885 (p. 346) 

 Body cyclopoid, metasome dilated and flattened, its segments 



strongly narrowed posteriorly 54 



54. First antennae 7-segmented; end segment of fifth leg broadly 



lamellar, ciliated on both margins; caudal rami little longer 

 than wide; littoral, among stones- 9 Hemicyclops Boeck, 1873 (p. 345) 

 First antennae 20- or 21-segmented; end segment of fifth leg 

 narrowly lamellar, margins smooth; caudal rami much longer 

 than wide; httoral, among algae cf 9 Euryte Philippi, 1843 



55. Second antennae nonprehensile, with 6 to 8 apical setae 56 



Second antennae prehensile, with 1 or more apical claws 58 



56. Head separated from first metasome segment; first antenna 



12-segmented, the ninth segment the longest; caudal rami 

 three or four times as long as wide; muddy bottom. 



cf 9 Cyclopinella G. O. Sars, 1913 

 Head fused with first metasome segment; end segment of second 



antenna longer than preceding segment 57 



57. First antennae 20-segmented; caudal rami six times as long as 



wide; end segment of fifth leg with 4 unequal setae; fifth leg 

 of male 4-segmented; dredged, moderate depths. 



9 Cyclopinodes, new genus (p. 319) 

 First antennae 1 6-segmented; caudal rami three times as long 

 as wide; end segment of fifth leg with 2 subequal setae; fifth 

 leg of male 3-segmented; fresh water. 



cf 9 Orthocyclops Forbes, 1897 (p. 329) 



58. Metasome cylindrical in female, scarcely narrowed posteriorly, 



pyriform in male; second antenna with 1 apical claw; first 

 antenna 7-segmented; gills of clams- 9 cf Myicola Wright, 1885, (p. 346) 

 Metasome pyriform in both sexes, narrowed posteriorly; second 

 antenna with 5 curved apical and unequal claws; first antenna 

 5-segmented; rectum of Echiurus cT 9 Goidelia Embleton, 1901 



59. Fifth leg replaced by 1 or more setae 60 



Fifth leg made up of a single segment 62 



Fifth leg made up of 2 segments 68 



60. Fifth leg replaced by 1 seta; second antenna nearly as long as 



first, its end segment with 4 long setae on the inner margin 



near the tip; pelagic, 2,000 fathoms cf 9 Conaea Giesbrecht, 1891 



Fifth leg replaced by 2 setae; second antenna much shorter 



than first 61 



71937—32 39 



