103 



broad than deep. Last pair of epimeral plates of metasome nearly rectangu- 

 lar, lateral corners drawn out to a very short point, First segment of uro- 

 some slightly depressed dorsally. Eyes comparatively small, rounded oval, 

 pigment red. Superior antennse in female about the length of the cephalon 

 and the 4 anterior segments of mesosome combined; 1st joint of the peduncle 

 more than twice as long as the other 2 taken together; tiagellum very slen- 

 der, nearly 3 times as long as the peduncle and composed of about 20 arti- 

 culations, the 1st of which is by far the largest; accessory appendage scarce- 

 ly exceeding l k of the length of the flagellum and 5-artieiilate, 1st joint 

 longer than all the others combined. Inferior antennse a little longer than 

 the superior, basal joint large and globular, tiagellum composed of about ."<) 

 articulations. Both pairs of antennae in male having the tlagella somewhat 

 longer than in female and composed of a much greater number of articulation-. 

 Anterior gnathopoda very powerful, propodos rather broad, quandrangular, 

 and longer than the carpus; palmar edge somewhat oblique and armed with 

 several denticles, 2 of which placed below are larger than the rest ; dactylus 

 rather strong and <[uite simple. Posterior gnathopoda with the propodos 

 about half the length of the carpus and oblong in form. Anterior pereiopoda 

 rather powerful, with the propodal joint curved and the dactylus unguiform; 

 posterior ones much more slender, penultimate pair the longest and having 

 the propodal joint very elongate and narrow. Last pair of uropoda with 

 both rami broadly lanceolate, the inner a little shorter than the outer. Tel- 

 son rounded, scarcely more long than broad, tip very slightly emarginatecl 

 in the middle and having 2 small denticles. Colour whitish. Length of adult 

 female 13 mm. 



Remarks. - The present form, originally described by Kroyer as an 

 Anonyx, was subserviently, as stated above, referred by Sp. Bate to the genus 

 Alibrotus of Milne-Edwards on account of the unusually elongated antennae 

 and the powerful structure of the anterior gnathopoda, in which respect it 

 certainly differs rather markedly from the genus Omnium*, to which it was 

 more recently referred by Boeck. 



Occurrence. - I have not myself met with this form olf the coast of 

 Norway. But Dr. Goes records its being found by Prof. Fries in the Yaran- 

 gerfjord, Finmark. Quite recently, too, Mr. Schneider told me that he bad 

 procured this form rather plentifully in the neighbourhood of Tromso by 

 sifting the muddy sand at the low water mark. It thus may in fact lie 

 regarded as a true littoral form, burying itself in the loose shingle whilst 

 the water retreates. In the Polar Sea it has often been observed in great 

 abundance at the verv surface of the water. 



