99 



not expanded laterally. Eyes distinct, subdorsal. Superior antennae well deve- 

 loped, with the flagelluni composed of numerous short articulations carrying long 

 olfactory filaments. Inferior antennae very much elongated, with a well-marked 

 scale-like appendage outside the' 3rd joint of the peduncle. Mandibles with the 

 cutting part divided from the molar expansion by a deep incision, palp rather slender. 

 Second pair of maxillae with the outer lobes narrow, conic in form, and tipped by a 

 limited number of simple setae. Maxillipeds normal. Legs nearly equal in length, 1 st 

 pair of same structure in the 2 sexes, prehensile, the carpus being very large, 

 subfusiform, and edged inside with spines, propodos narrow, linear, and very 

 movably articulated to the former, so as to admit of being bent in against it, 

 dactylar joint in all legs very small, 3-unguiculate. Uropoda largely developed, 

 with the rami slightly unequal, and clothed with fasciculated bristles. 



Remarks. — This genus was established as early as in the year 1813 by 

 Leach. The genera Oniscoda of Latreille, and Asellodes of Stimpson, as also that 

 of Renopomus Kroyer, are all undoubtedly identical with the Leachian genus, 

 which, as the much older one, ought to be retained. It is the type of the 

 family Ianiridce, and the genus which in external appearance exhibits most re- 

 semblance to the fresh-water genus Ascllus. Five species have as yet been re- 

 corded, viz., I. maculosa Leach, I. trieornis Kroyer, I. alta Stimpson, I.-ahyssorum 

 Beddard, and I. Tristani Beddard. Of these, only the first-named belongs to the 

 fauna of Norway. 



Ianira maculosa, Leach. 



(PI. XL.) 



Sjm: Oniscoda maculosa, M.-Edw. 

 „ Hcnopomus muticus, Kroyer. 



Specific Characters. — Body oblong oval in form, about 3 times as long as 

 it is broad, and slightly narrowed both in front and behind. Cephalon with the 

 lateral expansions evenly rounded, frontal edge straight, without a trace of rostrum. 

 Anterior segments of mesosome with the lateral parts slightly produced at both 

 corners, but not covering the small coxal plates, which are bi-lobulate. Caudal 

 segment sub-circular, distal part of lateral edges coarsely serrated. Eyes well 

 developed, rounded oval, with dark pigment. Superior antennae reaching about 

 to the end of the penultimate peduncular joint of the inferior ones, flagellum more 

 than twice as long as the peduncle, and composed of about 30 articulations. In- 

 ferior antennae considerably exceeding the length of the body, the last 2 pedun- 

 cular joints rather elongated, subequal, flagellum about twice the length of the 



