95 



Remarks. This form, recently described by Th. Scott, may, on a close 

 examination, be at once distinguished from any of the other species of My a by 

 the unusual production of the caudal rami. The structure of the 1st and last 

 pair of legs, moreover, is rather characteristic. 



Occurrence. On examining the preserved material collected during the 

 last 2 years from the sublittoral region off the west coast of Norway, at Aale- 

 sund, Kopervik and Bukken, I have succeeded in finding several specimens, both 

 females and males, of this distinct species. It also occurs off the Finmark coast, 

 as proved by the examination of some samples taken by Mr. Nordgaard and 

 kindly forwarded to me. 



Distribution. Scottish coast (Scott). 



59. Idya angusta, G. 0. Sars, n. sp. 



(PL LV, fig. 2). 



Specific Characters. Female. Body exceedingly slender and elongated, with 

 the anterior division, seen dorsally, oblong in form. Cephalic segment exceeding 

 in length that of the 3 succeeding segments combined, and, as usual, conically 

 produced in front. Epimeral plates discontiguous, being separated by deep lateral 

 incisions. Urosome extremely narrow, cylindrical in form, and exceeding half the 

 length of the anterior division, genital segment distinctly divided in the middle. 

 Caudal rami comparatively short, apical setae, however, much elongated. Anterior 

 antennae slender, with the 3rd joint rather elongated, exceeding in length both 

 the preceding and succeeding joints. First pair of legs less slender than in the 

 2 preceding species, 2nd joint of inner ramus scarcely longer than the 1st, last 

 joint imperfectly defined and having the apical claws comparatively elongated and 

 subequal, both penicillate at the tip. Last pair of legs unusually small, distal 

 joint oval in form, being scarcely more than twice as long as it is broad, one of 

 the marginal setae attached to about the middle of the outer edge. 



Colour not yet determined. 



Length of adult female 0.87 mm. 



Remarks. In the exceedingly slender and narrow form of the body, this 

 species bears a strong resemblance to a form described by Mr. A. Scott from 

 the Irish Sea as I. elongata. It differs very essentially, however, in the much 

 more slender and elongated anterior antennae, these appendages in the Irish form 

 being, on the contrary, unusually short and compact. The structure of the 1st 

 and last pairs of legs also seems, to judge from the figures given, to be rather 

 different in the 2 species. 



