160 



thin, without air-chambers or any branchial structure, inner plate lobular, except on 

 the 2 anterior pairs. Sexual appendage of male simple, conic; inner ramus of 

 both 1st and 2nd pairs of pleopoda transformed for copulative purposes. Uro- 

 poda with the basal part broadly expanded inside, and partly covered by the last 

 caudal segment, rami conically tapered, and, as a rule, terminating each in a 

 bunch of delicate hair-like bristles. 



Remarks. — I have found it advisable to establish this new family, to com- 

 prise a number, of genera, which have hitherto been referred to the family Ligiidce, 

 but which exhibit in common several characteristic features not found in the true 

 Ligiidce. The following 5 genera ought to be referred to the present family: 

 Trichoniscus, Trichoniscoides, HaplopMhalmus, Scyphacella, and Acioniscus. Of 

 these the first 3 are represented in the fauna of Norway, and will be treated 

 of below. 



Gen. 1. TriChOniSeUS, Brandt, 1833. 



Syn: Itea, Koch. 

 „ Philougria, Kinahan. • 



Generic Characters. — Body more or less oblong, attenuated behind. Ce- 

 phalon rounded in front, with small, though distinct lateral lobes. Side-plates of 

 the 3 posterior segments of mesosome more prominent than those of the 4 pre- 

 ceding segments. Metasome abruptly contracted, with the epimeral plates of the 

 2 anterior segments not concealed, last segment narrowly truncated at the tip, 

 and slightly emarginated on each side. Eyes small, but distinct, consisting of 

 only 3 visual elements imbedded in a dark pigment. Antennuhe witli the 1st 

 joint rather large and curved, last joint generally . longer than the 2nd. Antenna? 

 everywhere clothed with small appressed spikes, flagellum much shorter than the 

 peduncle, and gradually tapering distally.. Oral parts considerably prolonged, 

 giving the buccal mass a pronouncedly conical form. Left mandible with 2, right 

 with - only a single penicil behind the cutting part. Maxillipeds with the distal 

 joint of the basal part rather large and forming at the end outside a broad, 

 lamellar expansion finely ciliated at the edge, terminal part lanceolate, with the 

 outer 4 joints confluent, masticatory lobe nearly as large as the terminal part, 

 and terminating in a narrow, finely ciliated lash, epignath oblong linguiform, with 

 a rounded expansion at the base.- Legs of moderate size, slightly increasing in 

 length posteriorly, outer joints extremely spinous. Inner plate of first pair, of 



