COPEPODS OF THE WOODS HOLE REGION 573 



104. First exopod much longer than endopod; exopod of second 



antennae 1-segmented; basal segments of fifth legs reaching 



midline, not expanded; Httoral ? Fultonia T. Scott, 1902 



First endopod a Uttle longer than exopod; exopod of second 

 antennae 4-segmented; basal segments of fifth legs narrow, 

 not reaching midline; littoral, among algae.. 9 Tisbella Gurney, 1927 



105. The 2 segments of fifth legs completely fused 106 



The 2 segments of fifth legs distinctly separated 107 



106. Caudal setae as long as the body; second endopod considerably 



longer than exopod; all the legs tipped with very long 



plumose setae; sandy mud, shallow ? Psammis G. O. Sars, 1910 



Caudal setae half as long as body, or less; second endopod 

 much shorter than exopod; all exopod setae with plumes at 

 their tips; littoral, muddy bottom.. 9 Sigmatidium Giesbrecht, 1881 



107. Exopod of second antenna made up of 3 distinct segments 108 



Exopod of second antenna made up of 2 distinct segments 112 



Exopod of second antenna made up of a single segment.. 115 



Exopod of second antenna entirely lacking; basal expansion of 



fifth legs with 4 setae in female, 2 in male; end segment 



Unear, 6 setae; pelagic cf 9 Macrosetella A. Scott, 1909 (p. 281) 



108. Endopod of second antenna 3-segmented, with a distinct 



basipod to whose outer distal corner the exopod is attached 109 



Endopod of second antenna 2-segmented, without a basipod, 



exopod attached to side of proximal endopod segment 110 



109. Rami of first legs natatory and subequal in length; distal 



segment of fifth legs as wide as long, with 4 setae; rostrum 



short and blunt, muddy bottom, shallow c? 9 Zosime Boeck, 1872 



Rami of first legs prehensile, endopod much longer than 

 exopod; distal segment of fifth legs three times as long as 

 wide, with 6 setae; oyster washings (Ceylon). 



cf 9 Parastenhelia Thompson and Scott, 1903 



110. Rostrum entirely lacking; end segment of fifth leg projecting 



laterally, the same width throughout, 3-lobed at tip, each 



lobe with 1 seta; littoral, in algae 9 Halophytophilus Brian, 1918 



Rostrum present and well developed; distal segment of fifth 



leg not the same width throughout HI 



111. Rostrum notched near tip on either side; distal segment of 



fifth leg narrowed at base, widest at tip, longer than basal 



expansion; muddy bottom cf 9 Stenhelia Boeck, 1864 (p. 228) 



Rostrum smoothly rounded, no notches; distal segment of 

 fifth leg widest at base, narrowed at tip, shorter than basal 

 expansion; brackish mouths of rivers.- cf 9 Danielssenia Boeck, 1873 



112. Endopod of second antenna 3-segmented; endopods of second 



and third legs 2-segmented; body very long, narrow, and of 



uniform width throughout; sandy bottom, shallow. 



cf 9 Leptomesochra (part) G. O. Sars, 1911 

 Endopod of second antenna 3-segmented; endopods of second 



and third legs 3-segmented; body not of uniform width but 



apparently 3-parted; Httoral (Mediterranean). 



9 Peltthestris Monard, 1924 

 Endopod of second antenna 2-segmented; endopods of second 



and third legs 3-segmented, 2 distal segments of second legs 



sometimes fused 113 



71937—32 38 



