42 K 



Canadian Arctic Expedition, 1913-18 



Ri 1, and of a serrulate rostriform process of the reduced Ri 3; the subulate 

 process of Ri 2 is a generic character (Fig. 65 and 66). 



\ 



Fig. 65. D. stefanssoni <?. P 2 Ri. 

 Fig. 66. Same. P 2 Ri 3 enlarged, 





In the third leg of the male, Ri 2 is produced at its outer distal angle into 

 a strong mucronate process of rather complex form (Fig. 67). In the fourth 

 foot the distal angle of Ri 2 is produced into a slightly curved acuminate pro- 

 cess. 



Fig. 67. D. stefanssoni <?. P 3 Ri. 



The only other species with which the characters of the male D. stefanssoni 

 can be compared is D. sibirica G. Sars (1898, Jana Expedition op. cit. p. 343). 

 The hamate process on p 2 Ri is common to both. On the other hand, in 

 D. sibirica the reduced Ri 3 of the second foot of the male is without a rostri- 

 form process. This is the cardinal distinction, the presence in the one and the 

 absence in the other of a sharply defined character. The anterior antennae in 

 the female of D. sibirica are five-jointed. 



