Marine Copepoda 



41 K 



In D. typica, as figured by Sars, and in D.fusiformis, as figured by Brady, 

 the Ri 3 of p 4 has four setae, there being only one seta arising from the centre 

 of the inner margin of the joint. In both sexes of D. stefanssoni there are t hree setae 

 at the apex of p 4 Ri 3, namely a short se and two longer si; on the inner margin 

 of the joint there are two more si, a proximal one arising from the middle of the 

 inner margin, and a distal one inserted between this and the apex of the joint. 

 In D. sibirica Sars, p 4 Ri 3 has six setse in the female, five in the male. 



Fifth legs (p 69): hardly to be distinguished from D. sibirica, unless it is 

 by the interspacing of the marginal spines on the inner lamellar expansion ; 

 differing from D.fusiformis in the more proximal origin of the innermost mar- 

 -;inal spine of the inner lamella (Fig. 63). 



Fig. 63. D, stefanssoni. Fifth leg of female. 



In one case the distal joint of one side showed an aberration in the presence 

 of a long supernumerary spine at the inner side of the lobe, making a total of 

 six marginal spines instead of the normal number, five (Fig. 64). 



Fig. 64. D. stefanssoni. Aberrant fifth foot of female. 



In the male, the fifth legs are small, the rounded distal joint with five setae, 

 the reduced inner lobe with two unequal setse, as in D. typica. 



Description of male; length 1-01 mm.; anterior antennas subcheliform, as 

 in D. typica, figured by Sars. The second thoracic leg (p 2) offers distinctive 

 characters in the presence of a powerful hamate process on the inner side 



