NO. 5.] ACCOUNT OF THE SPECIES. 81 



appended (see fig. 3). The cephalic segment is well defined from the 1st 



pedigerous one, and is somewhat applanated in its anterior part, exhibiting 



about in the middle of the dorsal face a well-marked cervical depression (see 



fig. 2). The last pedigerous segment is imperfectly defined from the preceding 



one, though not fully coalesced with it. Its lateral corners are rounded off. 



The tail is composed of 4 well-defined segments, the 1st of which, the 



genital segment, is very large, attaining the length of the 2 succeeding ones 



combined. It exhibits dorsally, beyond the middle, a saddle-like depression, 



and is greatly protuberant below. In the specimen examined, a single large 



spermatophore was attached to the hind part of the segment below (see figs. 



1 & 2). The 3 succeeding segments rapidly diminish in size, the last, or 



anal segment, being rather small and imperfectly defined from the caudal 



rami. The latter are rather produced and narrowed distally, pointing straight 



backwards. They are conspicuously asymmetrical, the left ramus being much 



larger than the right, and less distinctly defined from the anal segment. Each 



ramus carries 5 plumose setae, 3 of which issue from the tip, the other 2 



from separate ledges of the outer edge. The middle apical seta of the left 



ramus is enormously prolonged, considerably exceeding in length the whole 



body, its outer part being unciliated and hair-like. As in most other Cala- 



noids, moreover, a small bristle is appended to the inner corner of each ramus. 



The eye is wholly absent, as proved by the examination of fresh Nor- 

 wegian specimens. 



The anterior antenna? (see figs. 1 & 2) are extremely slender, and some- 

 what longer than the body, extending, when reflexed, a Httle beyond the end 

 of the caudal rami. In all the specimens, they exhibit in their basal part an 

 abrupt curvature, whereas the outer, exfremely slender part is quite straight. 

 They are composed of the full number of articulations (25), of which the 1st 

 is by far the largest, and is somewhat compressed. Along the anterior edge 

 they are clothed with slender, somewhat unequal bristles, which, especially in 

 the proximal part, are densely crowded together. 



The posterior antennae, mandibles, maxilla, and anterior maxillipeds 

 closely agree in their structure with those appendages in the type species, 

 for which reason I have not considered it necessary to give figures of them. 

 In the next species, these limbs will be described in detail, and the differences 

 from those in the present species pointed out. 



