96 



Occurrence. Only a solitary female specimen of this form has as yet 

 come under my notice. It was taken, many years ago, at Her0, west coast of 

 Norway, the depth not being recorded. 



60. Idya finmarchica, G. 0. Sars, n. sp. 



(PL LVI). 



Specific Characters. Female. Body of comparatively robust form and 

 much depressed, with the anterior division, seen dorsally, broadly oval in form. 

 Cephalic segment considerably expanded, and about the length of the 3 succeed- 

 ing segments combined. Epimeral plates broad and rounded at the tips, sub- 

 contiguous. Urosome about half the length of the anterior division, and gradually 

 tapering distally, genital segment very distinctly divided in the middle, anal seg- 

 ment extremely small. Caudal rami somewhat produced, though comparatively 

 shorter than in 1. graeilis, innermost and outermost of the apical setae compara- 

 tively short, seta of outer edge placed about in the middle. Anterior antennae 

 rather short and stout, not nearly attaining the length of the cephalic segment, 

 2nd joint the largest, though scarcely longer than the 3rd. Posterior antennae and 

 oral parts, as also the natatory legs, of exactly the same structure as in I. fitr- 

 cata. First pair of legs, -however, rather different, with the rami comparatively 

 more slender, the inner one being, as usual, the longer and having the 2nd joint 

 of greater length than the 1st, though scarcely at all attenuated distally; last 

 joint very small, but well defined, and carrying on the tip 2 remarkably slender 

 subequal claws, both perfectly smooth. Terminal spines of outer ramus rather 

 slender, each with only a few cilia at the tip. Last pair of legs rather fully 

 developed, basal joint moderately expanded inside, with 2 of the marginal seta3 

 very small, terminal joint large, oblong fusiform in shape and densely hairy, one 

 of the marginal setae remote from the others, and attached somewhat beyond the 

 middle of the outer edge. Ovisac large. 



Colour not yet determined. 



Length of adult female 1.20 mm. 



Remarks. At first I believed this form to be the I. cluthce of Scott, on 

 account of the peculiarly slender form of the apical claws of the inner ramus of 

 the 1st pair of legs. Having recently, however, through the kindness of Th. 

 Scott, had the opportunity of examining one of his specimens, I find that these 

 2 forms are evidently specifically distinct the one from the other. I. cluthce is 

 a much smaller and more slender species, and has the anterior antennae consider- 



