COPEPODS OF THE WOODS HOLE REGION 563 



19. Distal segment of first endopod a little longer than proximal; 



distal segments of second and third endopods three times as 

 long as the proximal; fresh water, brackish pools. 



cf 9 Marshia Herrick, 1895 (p. 235) 

 Proximal segment of first endopod a little longer than distal; 

 segments of second and third endopods about equal in length 

 and very short; wet moss, woodlands (Bohemia) 



c? 9 Epactophanes Mrjizek, 1894 



20. Endopods of second and third legs obsolete; exopod of first legs 



2-segmented; fifth legs small, foliaceous, 2-segmented; first 

 antennae stout, 8-segmented; muddy bottoms, shallow. 



9 Leptopsyllus T. Scott, 1894 

 Endopods of second and third legs 1-segmented; exopod of first 

 legs 3-segmented; each fifth leg a 1-segmented oval lamella; 

 first antennae slender, 6-segmented; muddy bottoms, shallow. 



9 Stenocaris G. O. Sars, 1909 (p. 286) 

 Endopods of second and third legs with 2 or 3 segments 21 



21. Endopod of third legs made up of 3 segments 22 



Endopod of third legs made up of 2 segments 29 



22. Third, and often second, endopod modified for prehension, males 23 



Neither second nor third endopods modified for prehension, 



both sexes 27 



23. Endopods of first legs 2-segmented, shorter than exopod, of 



second and fourth legs 2-segmented, unmodified, of third legs 

 3-segmented, modified for prehension; in a holothurian. 



d' Abacola C. L. Edwards, 1891 



Both rami of first legs 1-segmented; exopods of second and 

 third legs 2-segmented, endopods 3-segmented; exopod of 

 fourth leg 3-, endopod 2- segmented; fifth legs lacking; littoral. 



d^ Syngastes Monard, 1924 



Endopods of first legs 2-segmented, much longer than exopods, 



very stout and tipped with a strong claw for prehension 24 



Endopods of first legs 2- or 3-segmented, as long as, or longer than, 

 the exopods, but natatory, slender, and armed with plumose 

 setae only 25 



24. Caudal rami long and cylindrical, with setae as long as urosome, 



first exopods usually 3-segmented; third exopods often slightly 

 modified; moderate depths, among algae. 



d" Laophonte Philippi, 1840 Cp. 262^ 

 Caudal rami short and lamellar, setae shorter than the rami; 

 first exopods always 2-segmented; third endopods only modi- 

 fied, exopods normal; tide pools, among algae. _ c? Asellopsis Brady, 1873 



25. Both second and third endopods 3-segmented and modified for 



prehension; endopod of first legs 3-segmented; exopod of 

 second antennae 2-segmented, 4 setae; on fresh-water plants. 



cf Canthocamptus Westwood, 1836 (p. 231) 

 Third endopod only modified, second endopod 2-segmented, un- 

 modified; endopod of first legs 2-segmented; exopod of second 

 antennae 1-segmented 26 



