COPEPODS OF WOODS THE HOLE REGION 565 



34. First antennae 9- or 10-segmented; exopod of second antenna 



4-segmented; rami of first legs about equal in length and 

 natatory, with setae only; muddy bottom, 30-50 fathoms. 



9 Neobradya T. Scott, 1892 



First antennae 8-segmented, more or less fused; exopod of 

 second antennae 4-segmented; inner expansion of fifth legs 

 reduced in both sexes; fresh water cf 9 Nitocrella Chappuis, 1924 



First antennae 8-segmented; exopod of second antenna 3-seg- 



mented, or less 35 



First antennae 6- or 7-segmented; exopod of second antenna 

 1-segmented 37 



35. Inner expansion of basal segment of fifth legs wholly lacking, 



distal segment, linear, five times as long as wide, 3 apical and 



1 inner setae; pelagic, 100 fathoms 9 Eremopus Brady, 1910 



Inner expansion of fifth legs well developed, distal segment 



shorter 36 



36. Inner expansion of fifth legs wider than distal segment, with 6 



setae; distal segment twice as long as wide; 2 apical, 2 outer, 



1 inner setae; fresh water, among plants. 9 Attheyella Brady, 1880 (p. 233) 

 Inner expansion of fifth legs a wide lamina, with 1 seta; distal 



segment as wide as long, with 4 setae; exopod of second 



antenna 2-segmented; pelagic (Antarctic)-- 9 Mawsonella Brady, 1918 



37. Rami of first legs equal, endopod natatory; inner expansion of 



fifth legs as wide as long, no longer than end segment, 4 setae, 



2 spines (Suez Canal) 9 Pseudomesochra Gurney, 1927" 



Endopod of first legs much longer than exopod; inner expansion 



of fifth legs much longer than wide, and longer than end segment 38 



38. Exopod of second antenna with 2 equal apical setae; inner ex- 



pansion of fifth legs in male with 1 seta, 2 spines; end seg- 

 ment with 3 setae; brackish water (^9 Apsteinia Schmeil, 1894 



Exopod of second antenna with 3 unequal apical setae; inner 

 expansion of fifth legs in male with 2 or 3 subequal setae; end 

 segment with 5 setae; brackish water, cf" 9 Mesoclira Boeck, 1865 (p. 237) 



39. Second segment of first antenna with large spine on outer margin 40 



Second segment of first antenna with setae only, no spine 41 



40. Fifth legs huge unsegmented laminae, covering the eggs; each 



caudal ramus with inner laminate process; apical seta en- 

 larged at base; muddy bottom, littoral. 



d" 9 Phyllopodopsyllua T. Scott, 1906 



Fifth legs normal, the 2 segments fused in female, separated in 

 male; caudal rami without inner processes, apical setae not 

 enlarged; muddy bottom, littoral cf 9 Orthopsyllus Brady, 1873 



41. Each fifth leg made up of basal segment only, end segment 



obsolete 42 



Both segments of fifth legs present, but completely fused 45 



Each fifth leg made up of 2 distinct segments, normally arranged 49 



42. Rami of first legs subequal in length; body extremely elongate 43 



Rami of first legs unequal in length; body moderately elongate.. _ 44 



" Name preoccupied by T. Scott in 1902; changed in MS. by Querney to Nannomesochra. 



