19 



the front narrowly rounded. Tail not attaining half the length of the anterior 

 division, and scarcely tapering behind; genital segment conspicuously constricted 

 in the middle, anal segment equalling in length the 2 preceding ones combined. 

 Caudal rami short, not nearly attaining the length of the anal segment, and 

 quadrangular in shape, seta of outer edge attached about in the middle, apical 

 setae of moderate length, the inner medial one about twice as long as the outer, 

 both coarsely ciliated, seta of outer corner much smaller than that of the inner. 

 Anterior antennae scarcely exceeding half the length of the cephalic segment, and 

 each composed of only 9 joints clothed with strong partly ciliated setae ; 5th joint 

 the longest, 6th about the length of the 3 outer joints combined. Posterior antennae 

 distinctly 4-articulate, 1st joint provided at the end on either side with a strong 

 ciliated seta, 2nd joint with a similar seta in front, 3rd joint with 4 such setae 

 outside, last joint about the length of the 2 preceding ones combined, and car- 

 rying on the tip 6 anteriorly-curving and likewise densely ciliated setae. Man- 

 dibular palp with the outer ramus composed of 4 well defined joints, inner ramus 

 with 3 ' comparatively short apical setae. Proximal outer lobe of the maxillary 

 palp much larger than the distal one and carrying 4 unusually thick plumose 

 setae. Maxillipeds very small and densely crowded, the anterior ones apparently 

 of normal structure, the posterior ones with the number of the terminal joints 

 much reduced. Natatory legs not exhibiting any pronounced peculiarity in their 

 structure. Last pair of legs consisting each of a rounded oval lamella attached 

 outside the last trunk-segment and provided with 3 thick and curved ciliated setae; 

 just above this lamella a thin bristle is attached to a conical projection of the 

 segment itself. 



Colour not yet ascertained. 



Length of adult female 0.60 mm. 



Remarks. The present form cannot be confounded with any of the other 

 Cyclopinida 1 , exhibiting, as it does, a most characteristic appearance, somewhat 

 recalling that found in certain of the semi-parasitic forms, to which, indeed, I was 

 at first inclined to refer it, before having made out its anatomy. 



Occurrence. Only 3 specimens of this remarkable form, all of the female 

 sex, have hitherto come under my notice. They were picked up from a sample 

 taken last summer at Riser, south coast of Norway, in a depth of about 40 

 fathoms, muddy sand. All 3 specimens have been sacrified for dissection, in 

 order to get a satisfactory conception of the structure of the very small and 

 densely crowded oral parts. The specific name here proposed alludes to the 

 difficulty experienced in the examination of these parts.- 



