30 



appearance to the 2 outermost setae of the distal joint. Ovisac comparatively 

 small, with a very limited number of ova. 



Colour of the living animal not yet ascertained. 



Length of adult female 0.51 mm. 



Remarks. The present species is especially distinguished by the 

 peculiar structure of the last pair of legs, which is unlike that in any other 

 known species, though by the strong development of some of the marginal 

 setae somewhat recalling that in E. gothiceps Giesbrecht. The rudimentary 

 condition of the innermost seta in the distal joint is however very characteristic 

 and quite peculiar to the present species. 



Occurrence. Two female specimens only of this form have as yet 

 come under my notice. One of them was picked up from a sample taken at 

 Korshavn from a depth of about 30 fathoms; the other specimen was found 

 last summer at Hvaler, outside the Christiania Fjord. 



21. Ectinosoma obtusum, G. O. Sars, n. sp. 



(PI. XVIII, fig. 2). 



Specific Characters. Female. Body comparatively short and stout, 

 with the anterior division slightly dilated in the middle. Cephalic segment 

 scarcely exceeding in length the 3 succeeding segments combined and, seen 

 dorsally, obtusely rounded anteriorly, the rostral plate being abruptly deflexed 

 and scarcely at all prominent in front. Urosome somewhat exceeding in length 

 the exposed part of the trunk and gradually tapered behind. Caudal rami 

 very short, scarcely as long as they are broad; apical setae of moderate length. 

 Anterior antennae comparatively slender and attenuated, 7-articulate. Posterior 

 antennae with the outer ramus less fully developed than in the preceding 

 species, and not nearly extending as far as the inner. Anterior maxillipeds 

 with the 2nd basal joint somewhat larger than the 1st. Natatory legs of the 

 usual structure. Last pair of legs built on the same type as in E. melaniceps 

 and allied species; distal joint comparatively broad and somewhat oblique, with 

 a small tuberculiform prominence inside the middle, terminal edge irregularly 

 lobular, and exhibiting, somewhat outside the middle, a deep incision separating 

 the outermost lobe from the other 2, which are closely juxtaposed and occupy 

 the most prominent part of the joint; marginal setae of moderate length and 

 somewhat unequal, the innermost one being the shortest, but of rather coarse 

 structure, almost spiniform ; appendicular bristle very small and attached to a 

 well defined lobule issuing from the edge immediately inside the outermost 



