119 



lanceolate, pointing anteriorly. Legs, at least in female, of uniform structure, 

 simple, ambulatory, but slightly increasing in length posteriorly, dactylus bi- 

 unguiculate. Dropoda issuing from the ventral face of the caudal segment, com- 

 paratively small, biramous, rami linear. 



Remarks. — The systematic position of this genus is somewhat doubtful. 

 In several characters, for instance the total absence of eyes, the structure of 

 the oral parts, and partly also of the caudal appendages, it certainly agrees per- 

 fectly with the other Desmosomidce ; but the general form of the body is some- 

 what different, and the structure of the antenna? and legs resembles more that 

 in the Ianiridce, and perhaps therefore it should more properly be included 

 in that family. Besides the type species described below, another nearly-allied 

 species has recently been detected in the Caspian Sea (A 7 , caspius G. 0. Sars). On 

 the other hand, the form described by the present author from the Norwegian 

 North Atlantic Expedition as A 7 , hicuspis, is scarcely congeneric, differing, as it 

 does, considerably, in the structure of both the antennae and the oral parts, and 

 also in that of the caudal appendages. 



Nannoniseus oblongus, G. 0. Sars. 



(PL L.) 



Nannoniseus oblo-ngas, G. 0. Savs, Nye Dybvandscrustaceer fra Lofoten. Ohr. Vid. Selsk. Forli. 



1869, p. 164. 



Specific Characters. — Body of female rather regularly oblong oval, nearly 

 3 times as long as it is broad, and but very slightly narrowed behind; that of 

 male with the posterior division, comprising the last 3 segments of mesosome and 

 the caudal segment, much narrower than the anterior. Cephalon in both sexes very 

 large, with the lateral parts projecting, outside the antennae, to an acute, anteriorly 

 pointing corner, frontal part very prominent, and minutely incised at the tip. 

 Lateral parts of the 4 anterior segments of mesosome projecting in front as acute 

 lappets; those of the 3 posterior segments subtruncate and quite contiguous. 

 Caudal segment larger in female than in male, being in both sexes semi-oval in 

 outline, with the tip evenly rounded. Superior antennae scarcely extending beyond 

 the tip of the frontal part, 1st joint rather thick, 2nd of about the same length, but 

 much narrower, flagelluni extremely small, its olfactory papilla very large, almost 

 globular. Inferior antenna?, of essentially same structure in the two sexes, scarcely 

 attaining half the length of the body, spine of the 3rd peduncular joint of mo- 

 derate length and pointing slightly outwards, flagelluni slender 8 — 10-articulate. 

 1st pair of legs in female of the very same structure as the others, in male, how- 



