191 



is much the largest. Candal rami comparatively small, with the normal number 

 of setae. Eye wholly absent. Anterior antennae of moderate length, 6-articulate, 

 3rd joint much the largest, the outer 3 joints forming together a well defined 

 terminal part very movably articulated to the preceding joint and clothed at 

 the end with long diverging setae. Posterior antennae smaller than the anterior 

 and more or less strongly curved, being composed of only 3 joints, the last 

 of which is provided at the end with long rigid setae curving anteriorly. Max- 

 illae armed at the incurved extremity with 2 short movable claw-like spines; 

 palp sub-clavate in form, with a limited number of small marginal setae. An- 

 terior maxillipeds biarticulate, distal joint carrying on the end 2 digitiform 

 appendages coarsely spinulose on the inner edge. Posterior maxillipeds power- 

 fully developed in both sexes and distinctly prehensile, propodos more or less 

 dilated, dactylus slender and very mobile, especially in male. Natatory legs 

 with the outer ramus more strongly built than the inner and armed outside 

 and at the tip with coarse dagger-like spines, inner ramus with the terminal 

 joint much produced, especially in the posterior pairs, assuming in the latter a 

 narrow linear form. Last pair of legs small, bisetose. Two ovisacs present in 

 female, attached somewhat dorsally, so as partly to cover the tail. 



Remarks. This genus was established as early as the year 1843 by 

 Philippi, to include a mediterranean species (O. venusta). The genus Antaria 

 of Dana is identical with Philippi's genus. No less than 10 different species 

 are recorded by Giesbrecht in his great work. They all are very nearly 

 related, and in some cases not easy to distinguish without a very close ex- 

 amination. The chief distinguishing characters refer to the relative size of the 

 genital segment in the female, the length of the caudal rami, and partly also 

 the mutual length of the outermost and innermost apical seta of the tail. Two 

 Norwegian species of this genus will be described below. 



103. Oncaaa borealis, G. O. Sars, n. sp. 



(PI. CVIII). 

 Syn: Onccea conifera, G. O. Sars (not Giesbrecht). 



Specific Characters. Female. Body comparatively slender, with the 

 anterior division oblong fusiform in outline, greatest width scarcely attaining 

 half the length, and occurring about in the middle, 2nd trunkal segment, as 

 in 0. conifera, raised dorsally in the form of an hump-like prominence. Tail 

 about half the length of the anterior division; genital segment scarcely longer 

 than the remaining part of the tail, and gradually somewhat narrowed behind; 



