48 



20. Xanthocalanus propinqvus, G. 0. Sars, n. sp. 



(PI. XXXIII). 



Specific Characters. Female. Form of body resembling that of the pre- 

 ceding species, though somewhat less slender. Last segment of metasome defined 

 from the preceding one by a distinctly marked suture, lateral lappets compara- 

 tively shorter than in X. borealis, scarcely reaching to the middle of the genital 

 segment. Urosome about y 3 as long as the anterior division of the body; 

 caudal rami longer than they are broad. Anterior antennae very slender, reaching 

 when reflexed, to the end of the 2nd caudal segment. Posterior antennae with 

 the outer ramus considerably longer than the inner. Oral parts almost exactly 

 as in the preceeding species. Natatory legs likewise of a very similar structure, 

 except that the spinules on the inner ramus of the 4th pair are arranged in a 

 single oblique row. Last pair of legs comparatively shorter and more robust, 

 basal joint coarsely spinulose inside, 2nd joint of about same breadth throughout, 

 last joint much shorter and rather broad at the base, carrying an oblique row 

 of 4 spines, the innermost of which is much coarser than the others. 



Male resembling that of the preceding species, though somewhat differing 

 in the structure of the last pair of legs, which are very asymmetrical, the right 

 leg being extremely reduced in size, scarcely even reaching to the middle of the 

 1st joint of the left one. 



Colour whitish, pellucid, without any conspicuous pigment. 



Length of adult female 1.75 mm. 



Remarks. This form is closely allied to the preceding species, but of 

 much smaller size, and somewhat less slender of form. It may, moreover, be 

 easily distinguished by the well-marked separation of the last segment of the 

 metasome from the preceding one, as also by the somewhat different structure of 

 the last pair of legs in both sexes. 



Occurrence. Several specimens of this form were collected many years 

 ago by the present author at Selsovig on the Nordland coast, located just within 

 the Polar circle. They were procured by the aid of the dredge from a depth of 

 about 100 fathoms. This species also occurs occasionally off the west coast of 

 Norway, some few specimens having recently been found among those of X. borealis 

 collected in this region. 



