70 G. 0. SARS. CRUSTACEA. [NORW. POL. EXP. 



anal segment shorter than the preceding one. Caudal rami comparatively 

 narrow, about 3 times as long as they are broad, and separated by a rather 

 broad interval, though scarcely at all divergent, tip obtusely truncated, with 

 a slight angular projection outside the caudal setae; the latter 4 in number, 

 and of moderate length. Anterior antennae in female, when reflexed, reaching 

 somewhat beyond the middle of the tail, and composed of 23 articulations, 

 the 1st and 7th much larger than the others. Posterior antennas and oral 

 parts about as in the type species. Natatory legs likewise of a very similar 

 structure, though comparatively somewhat more slender. Last pair of legs in 

 male extremely slender, right leg with the terminal styliform part occupying 

 more than half its length. Length of adult female 2'40 mm., of male 

 1-80 mm. 



Remarks. This form so very closely resembles the type species, that 

 I should have been much inclined to regard it only as a large variety, if both 

 forms were not found together in the very same samples, without exhibiting 

 any transitions. On a closer examination, indeed, some few minor differences 

 may be also proved to exist in the structural details. 



Description of the female. 



The average length of adult specimens is 2'40 mm, whereas in the type 

 species it scarcely exceeds 1'40 mm. 



The general form of the body (see figs. 1 and 2) is rather slender and 

 elongated, though perhaps somewhat less so than in the type species. The 

 anterior division is but slightly vaulted above (see fig. 2), and, seen dorsally 

 (fig. 1), exhibits a rather regular oblong oval form, with the greatest width 

 about in the middle, and gradually narrowed both in front and behind. The 

 anterior extremity appears narrowly rounded, the posterior somewhat broader 

 and slightly emarginated in the middle. The cephalic segment is completely 

 coalesced with the 1st pedigerous one, and the same is also the case with 

 the last 2 segments, the whole division being accordingly composed of only 

 4 distinctly-defined segments, the 1st of which is nearly twice as large as 

 the other 3 combined. The lateral parts of the last segment are rounded off, 

 and the front carries below, as in the type species, 2 very delicate tentacular 

 filaments. 



