90 



G. 0. SARS. CRUSTACEA. [norw. pol. exp. 



the genital segment, exceeds in length the other 2 combined, and is but 

 slightly dilated in its anterior part. The last segment (see PI. XXVII, fig. 11) 

 is a little longer than the preceding one, and is rather obliquely truncated on 

 each side at the junction with the caudal rami. The latter (ibid.) are perfectly 

 symmetrical and produced to an unusual degree, being about the length of the 

 last 2 segments combined, and are linear in form, pointing straight behind. 

 They each carry 5 densely plumose setae, 3 of which issue from the narrowly 

 rounded tip, the other 2 from distinct ledges of the outer edge. One of the 

 latter is placed at rather a long distance from the other, in front of the 

 middle of the outer edge. The middle apical seta, or the innermost but one, 

 is much longer than the others, and terminates in a very slender filament, 

 curved outwards (see PI. XXVI, fig. 1). Moreover, as in most other Calanoids, 

 a very slender and delicate, uncihated bristle originates from the upper face 

 of each ramus, close to the inner corner. 



No trace of any eye could be detected in the preserved specimens. 



The anterior antenna (see PI. XXVI, figs. 1, 2) are exceedingly slender 

 and elongated, the 5 distal joints projecting, when reflexed, beyond the tips 

 of the caudal rami. They are composed of 25 well-defined articulations, 

 which are clothed anteriorly with delicate bristles. The penultimate and 

 antepenultimate articulations each carry, moreover, at the end posteriorly, a 

 remarkably large and densely plumose seta (see PI. XXVII, fig. 2). 



The posterior antennae are very greatly developed, projecting far from 

 the sides of the body (see PI. XXVI, fig. 1). In structure, they exhibit several 

 peculiarities (see PI. XXVII, fig. 3). Thus the basal part is rather slender 

 and quite naked, without any trace of the usual plumose setae in front, and 

 it is, moreover, considerably produced at the inner comer, so that the 

 2 rami issue at some distance from one another. At the insertion of the inner 

 ramus, it projects to a small triangular lappet, at the base of which a small 

 hair is attached. The inner ramus, which generally forms, with the basal part, 

 a geniculate bend, consists, as usual, of 2 joints, the 1st of which is the 

 larger, and is densely ciliated along the somewhat convex hind edge, but with- 

 out any setae anteriorly. The last joint is oblong oval in form, and slightly 

 bilobular at the tip, carrying about 10 setae, some of which are exceedingly 

 long and slender. The outer ramus is a little longer than the inner, is cylin- 

 drical in form, and composed of only 5 joints, the 1st of which is imper- 



