99 



62. Idyopsis pusilla, G. 0. Sars, n. sp. 



(PL LVII, fig. 2). 



Specific Characters. Female. Anterior division of body less expanded 

 than in the preceding species. Cephalic segment moderately dilated, and not 

 nearly twice as long as the 3 succeeding segments combined. Epimeral plates 

 comparatively broader and less extant, especially those of the last pair, which 

 are obtuse at the tip. Urosome, as in the preceding species, rather short, genital 

 segment less expanded, but more deeply indented on each side in the middle. 

 Eye inconspicuous. Anterior antennse comparatively shorter and stouter than in 

 I. clilatata, with the terminal part about the length of the 2 preceding joints 

 combined. Posterior antennae with the first 2 joints distinctly defined, outer ramus 

 comparatively short, but distinctly 4-articulate. Anterior maxillipeds remarkably 

 large and robust, claw of outermost lobe coarsely spinulose on the one edge. 

 First pair of legs closely resembling in structure those in I. clilatata, but with 

 the outer ramus somewhat longer than the 1st joint of the inner. Last pair of 

 legs with the proximal joint quite short, but produced inside to a narrow lingui- 

 form lamellar expansion, carrying on the tip 3 setse, the middle one rather elon- 

 gated; distal joint narrow fusiform in outline, seta of outer edge placed close to 

 the apex. 



Colour whitish. 



Length of adult female 0.43 mm. 



Remark*. Though nearly allied to the preceding species, and evidently 

 congeneric with it, this form is at once distinguished by the less expanded an- 

 terior division of the body, as also by the comparatively shorter and stouter an- 

 terior antennse. The last pair of legs, also, are rather different in the 2 species. 



Occurrence. Only 2 female specimens of this form have hitherto come 

 under my notice. They were found, many years ago, at Mager0, south of the 

 entrance to the Trondhjem Fjord, in a depth of about 40 fathoms. 



Gen. 26. Idyella, Gr. 0. Sars, n. 



Generic Characters. General form of body rather resembling that in 

 Idya, the 2 chief divisions being very sharply defined from one another. 

 terior antennse comparatively short, and angularly bent at the b;> 



