596 BULLETIN 159, UNITED STATES NATIONAL MUSEUM 



114. Exopods and endopods each with the same number of seg- 



ments in the first 4 pairs of legs, but unhke each other 115 



Exopods and endopods each with a different number of seg- 

 ments in the first 4 pairs of legs, some of them often lacking 123 



115. Exopods 3-segmented, endopods 2-segmented 116 



Exopods 2-segmented, endopods 3-segmented or 1-segmented 121 



Exopods 1-segmented, endopods 2-segmented or lacking 122 



116. Urosome of female 4-segmented, of male 5-segmented 117 



Urosome of female 3-segmented or 2-segmented, male unknown 120 



117. Second antenna 4-segmented, without an exopod, with apical 



setae; fifth legs lacking; caudal setae shorter than the 

 caudal rami; in compound ascidian. 



cT ? Ophthalmopachus Hesse, 1866 

 Second antenna 3- or 2-segmented, no exopod; fifth legs present 118 



118. Second antenna 2-segmented, with 5 apical setae; first antenna 



1 1-segmented, sparsely setose; fifth leg a small knob with a 



single seta; pelagic, deep water ? Paroithona Farran, 1908 



Second antenna 3-segmented, armed with prehensile claws 119 



119. Second antenna with 1 stout apical claw; first antenna 7- 



segmented, sparsely setose; fifth leg a small knob with 2 



unequal setae; in a holothurian cf ? Synapticola Voigt, 1892 



Second antenna with 2 stout apical claws; first antenna 6- 

 , segmented, densely setose; fifth leg laminate, 2-segmented, 

 with marginal spines; in a holothurian. 



cf 9 Colaceutes Hartmann, 1856 



120. First antenna 6-segmented; second antenna 3-segmented, 



without an exopod, with 4 apical geniculate setae; fifth leg 

 2-segmented, with 4 setae; in echinoderms. 



? Synatiphilus Canu and Cuenot, 1892 

 First antenna 13-segmented; second antenna 4-segmented, 

 with 1-segmented exopod, and 8 straight apical setae; fifth 

 leg 1-segmented, with 2 tiny setae; pelagic, moderate depths. 



9 Oithonopsis Brad}', 1915 



121. Endopods 3-segmented; genital segment and abdomen fused; 



fifth leg laminate, 1-segmented, with apical chela; caudal 



rami widely separated; on a serpulid 9 Bactropus Gravier, 1912 



Endopods 1-segmented; urosome segments separated; fifth 

 leg a knob with 1 seta; second antenna 4-segmented, with 3 

 apical claws and no exopod; on an annelid. 



9 Seridium Giesbrecht, 1897 



122. Endopods 2-segmented; first antenna 3-segmented; second 



antenna 3-segmented, with 1 seta; fifth leg a 1-segmented 

 lamina, with 4 marginal setae; in brittle stars. 



cf 9 Enterognathus Giesbrecht, 1900 

 Endopods lacking; first antenna 1-segmented; second antenna 

 1-segmented, papilliform; fifth legs lacking; fifth and genital 

 segments fused; in an ophiurian. 



cf 9 Chordeuroium Stephensen, 1918 



