374 



Page 135. 

 Add the following species: 



Idomene borealis, G. 0. Sars, n. sp. 



(Suppl. PI. 13, fig. 2). 





Specific Characters. Female. General form of body resembling that in 

 the type species, though perhaps a little shorter and stouter. Cephalic segment 

 large and evenly rounded in front, with a very small deflexed rostral expansion. 

 Epimeral parts of this and the 3 succeeding segments sub-imbricate and acutely 

 produced at the hind corner. Last pedigerous segment much narrower than the 

 preceding ones, but provided with well defined acute epimeral plates. Urosome 

 not nearly attaining half the length of the anterior division ; last segment short 

 and scarcely cleft behind. Caudal rami rather short, being scarcely longer than 

 they are broad, apical setaa comparatively short, the innermost one not spiniform. 

 Anterior antennae rather small, and resembling in structure those in the type 

 species. Posterior antenna with the outer ramus comparatively smaller, but 

 distinctly 3-articulate. Mandibular palp with the rami much smaller than in the 

 type species, none of the seta3 spiniform. Maxillse and maxillipeds about as in 

 that species. 1st pair of legs with the outer ramus much shorter than the 1st 

 joint of the inner, this joint less dilated than in the type species and having the 

 seta of the inner edge attached in front of the middle, last joint of same ramus 

 rather small, scarcely longer than the preceding one, apical claws more slender 

 than in the type species. SetaB of this and the preceding joint small and not 

 plumose. Last pair of legs with the distal joint narrowly exserted at the tip, 

 with only the 2 outermost setse spiniform, seta of inner edge attached in front 

 of the middle; inner expansion of proximal joint angularly incurved at the base 

 outside and comparatively narrower than in the type species, marginal seta? 6 in 

 number and of rather unequal size, the innermost but one reduced to a very 

 short denticulated spine. 



Colour, when alive, not yet ascertained. 



Length of adult female 0.42 mm. 



Remarks. This form at first sight looks very like I. forcipata Phil. On 

 a closer examination, however, it may at once be distinguished by the compara- 

 tively shorter caudal rami, and more particularly by the innermost apical seta 

 not being spiniform. As mentioned in the above diagnosis, moreover, several 

 other well marked differences in the structural details are found to exist. 



