COPEPODS OF THE WOODS HOLE REGION 577 



131. Terminal segment of endopods of second legs enormously 



lengthened; basal expansion of fifth leg very narrow and 

 tipped with 1 seta; littoral, among algae. 



d^ ? Longipedia Claus, 1863 (p. 170) 

 Second endopod not lengthened; basal expansion of fifth leg 

 wide, with several setae; first antennae 17-segmented, basal 

 segments enlarged; pelagic, surface tow. 



9 Benthomesophria G. O. Sars, 1909 

 Second endopod not lengthened; basal expansion of fifth leg 

 very short, with 5 setae; first antennae 5-segmented, long 

 aesthetask on third segment; marine, Banyuls. 



9 Tisemus Monard, 1928 

 Second endopod not lengthened; first antennae 6- to 9-seg- 



mented 132 



132. One or both rami of first legs prehensile, armed with claws 133 



Both rami of first legs natatory, armed with plumose setae 160 



133. Exopods of first legs distinctly longer than endopods 134 



Endopods of first legs distinctly longer than exopods 135 



Rami of first legs equal or subequal 155 



134. Exopod of second antenna 4-segmented; exopod of first legs 



tipped with 5 or 6 short curved claws, subequal; fifth legs 

 small, not reaching ovisac; littoral, brackish pools. 



cf 9 Tigriopus Norman, 1868 

 Exopod of second antenna 2-segmented; exopod of first legs 

 tipped with 2 or 3 long unequal claws; fifth legs large, often 

 covering the ovisacs; littoral, among algae. 



cf 9 Thalestris Claus, 1863 (p. 201) 

 Exopod of second antenna 2-segmented; exopod of first leg 

 tipped with 4 subequal curved claws; fifth legs small; first 

 antennae 7-segmented; Lake Baikal cf 9 Harpacticella Sars, 1908 



135. Metasome passing insensibly into urosome; basal segment of 



first endopod usually longer than entire exopod 136 



Metasome abruptly narrowed at fifth segment; basal segment 



of first endopod longer than entire exopod 140 



Metasome abruptly narrowed at fifth segment; basal segment 



of first endopod not longer, usually shorter, than exopod 142 



136. Exopod of second antenna 2-segmented, distal segment the 



longer; distal segment of fifth legs usually with 6 unequal 

 setae, basal expansion with 4 setae; moderate depths. 



cf 9 Schizopera G. O. Sars, 1905 



Exopod of second antenna made up of a single segment 137 



Exopod of second antenna 2-segmented, proximal segment the longer. _ 138 

 Exopod of second antenna 3-segmented, middle segment very short 139 



137. First antennae of female straight; end segment of second 



endopod with 1 inner and 2 apical setae, and 1 apical spine; 



rostrum obsolete; httoral, among algae. & 9 Ameira Boeck, 1865 (p. 244) 

 First antennae of female geniculate at third segment; end 



segment of second endopod with 2 inner, 2 apical setae, 1 



spine; rostrum large; parasitic on a worm. 



9 Nitocrameira Liddell, 1912 

 First antennae of female geniculate at second segment; end 



segment of second endopod with 2 inner, 1 apical setae, 1 



spine; rostrum short and blunt; muddy bottoms. 



cf 9 Diosaccopsis Brian, 1925 



