COPEPODS OF THE WOODS HOLE REGION 581 



162. Basal expansion of fifth legs in female wider than end 



segment, with 5 subequal setae, in male narrower, 

 with 2 setae; muddy bottom, shallow — cT 9 Robertsonia Brady, 1880 

 Basal expansion of fifth legs in female not wider than end 

 segment, with 4 unequal setae, the second outer seta very 

 much elongated (Norwegian fiords) __ ? Pseudameira G. O. Sars, 1911 



163. Endopod of first leg nearly twice as long as exopod, its basal 



segment widened; metasome depressed, one-third wider 

 than the urosome; Norwegian coast, 12 fathoms. 



9 Tachidiella G. O. Sars, 1909 

 Rami of first leg subequal; basal endopod segment not widened 164 



164. Metasome compressed laterally, no wider than urosome; basal 



expansion of fifth leg with 2 setae, end segment 3-lobed, 



with 3 setae; muddy sand, shallow 9 Pseudobradya G. O. Sars, 1904 



Metasome compressed laterally, wider than urosome; basal 

 expansion of fifth leg with 1 seta, end segment not lobed, 

 with 2 setae; surface tow (New Zealand) 9 Phroso Brady, 1899 



165. Exopod of second antenna 4-segmented; basal expansion of 



fifth legs entirely lacking, or nearly so, without setae 166 



Exopod of second antenna 3-segmented; basal expansion of 



fifth legs well developed and armed with plumose setae 169 



166. Rostrum broadly triangular and prominent; genital segment 



with a short spiny projection on either side at the posterior 



corner 167 



Rostrum small and insignificant; genital segment with smooth 



posterior corners, without spiny projections 168 



167. Caudal rami so closely appressed as to appear fused, 10 to 20 



times as long as wide; second segment of first antenna with- 

 out a spine; pelagic, 100 fathoms 9 Cerviniopsis G. O. Sars, 1903 



Caudal rami separated, four or five times as long as wide; 

 second segment of first antenna with a stout, acute spine on 

 its outer margin; pelagic, 50 fathoms 9 Eucanuella T. Scott, 1901 



168. Basal segment of second endopod with 2, of third endopod 



with 1, large spine on inner margin; caudal rami five to ten 



times as long as wide; muddy bottoms 9 Cervinia Norman, 1878 



Basal segments of second and third endopods with normal 

 setae, no spines; caudal rami only a very little longer than 

 wide; sandy bottoms & 9 Tachidiopsis G. O. Sars, 1911 



169. Body compressed, urosome as wide as metasome; distal exopod 



segment of second antenna longer than the 2 proximal seg- 

 ments combined 170 



Body depressed, metasome wider than urosome; middle exopod 

 segment of second antenna very short, the other 2 segments 

 much longer 171 



170. Middle apical seta of caudal rami as long as the body; inner 



seta of end segment of fifth leg very short, weak, and rudi- 

 mentary; pelagic, surface tow. 



cf 9 Microsetella Brady and Robertson, 1873 (p. 176) 

 Middle apical seta of caudal rami shorter than urosome; inner 

 seta of end segment of fifth leg as long and stout as the outer; 

 muddy bottoms cf Pseudobradya G, O. Sars, 1904 



171. Fifth legs small, basal expansion with only 1 or 2 setae 172 



Fifth legs large, basal expansion with 5 or 6 setae 173 



