53 



Antennae and oral parts built on the very same type as in the 2 other known 

 species. 1st pair of legs likewise of a very similar structure, the inner ramus 

 being considerably longer than the outer, and only composed of 2 joints very 

 sharply defined from each other, the distal one slightly shorter and much 

 narrower than the proximal one, and armed at the tip with 2 exceedingly 

 slender claw-like spines accompanied inside by a small bristle; inner edge of 

 this joint carrying 2 somewhat larger setae. The 3 succeeding pairs with the 

 basal part rather broad and flattened, rami slender and of nearly equal length. 

 Last pair of legs very narrow, with the proximal joint simple cylindric in shape, 

 not expanded inside, distal joint a little longer than the proximal one, and 

 conically tapered, with 3 small setas on the tip and another somewhat larger 

 seta inside near the base. 



Colour of the living animal not yet ascertained. 



Length of adult female 0.58 mm. 



Remarks. The above-described form is unquestionably referable to the 

 genus Idyella, as defined by the present author, exhibiting, as it does, a struc- 

 ture of the several appendages very similar to that found in the 2 other known 

 species. It is however of considerably larger size than either of them and 

 also of a comparatively more robust form of the body. 



Occurrence. A solitary female specimen only of this form has as yet 

 come under my notice. It was found in a sample taken some years ago out- 

 side Christiansand from a depth of about 30 fathoms. 



42. Idyella exigua, G. O. Sars. 



See Vol. V, p. 101, PI. LVIII, fig. 2. 

 (PI. XXXIII, fig. 2). 



Remarks. The female of this species has been described and figured 

 in Vol. V from some specimens taken at Bukken, south west coast of Norway. 

 I have subsequently found this form not unfrequently in several places on the 

 south coast, Korshavn, Lillesand, Riser, in depths ranging from 20 to 60 fathoms. 

 Male specimens are very rarely met with, and may also easily escape attention 

 on account of their small size. On the accompanying plate I have given 

 some detail-figures of such a specimen, elucidating the rather well-marked 

 sexual differences in the structure of the anterior antennae and the 2nd and 

 last pairs of legs. 



8 Crustacea. 



