199 



other 2 combined, and forming posteriorly a slight laminar expansion edged 

 with delicate ciliated bristles, flagellum fully twice the length of the peduncle' 

 and composed of about 12 articiilations, the 1st of which is but little longer 

 than the succeeding ones; accessory appendage about half as long as the 

 peduncle. Inferior antennae a little longer than the superior, last joint of 

 the peduncle exceeding in length the penultimate one, flagellum rather 

 slender, and nearly as long as the peduncle, Anterior gnathopoda with the 

 propodos about the length of the carpus, the latter but sliglitly dilated. 

 Posterior gnathopoda much more slender, with the propodos sublinear in 

 form, and considerably longer than the carpus. Penultimate pair of pereiopoda 

 with the basal joint oblong quadrangular, infero-posterior corner nearly right- 

 angled. Last pair of pereiopoda a little shorter, but with the basal joint 

 considerably larger, and produced interiorly to a sharp corner, its posterior 

 edge somewhat arcuate, and finely serrated. Last pair of uropoda with the 

 rami nearly twice as long as the basal part, and round about edged with 

 •short denticles. Telson about twice as long as it is broad at the base, outer 

 part tapering to a point, cleft very narrow, and extending about to the 

 middle. Colour light yellowish, variegated with brownish patches, sometimes 

 assuming a rather regular quadrangular form, antennae and legs banded with 

 reddisli brown. Length of adult female 25 mm. Maximum size of arctic 

 specimens (according to Dr. Hansen) reaching 47 mm. 



Brmarls. — The present species may be regarded as the type of the 

 genus, since it was the form, upon which Kroyer established his genus. As 

 mentioned above, Boeck, and most subsequent authors, have erroneously iden- 

 tified Kroyer's species with the form desi-ribed long before by Phipps as 

 Cancer ampitlln; but Dr Hansen is certainly quite right in regarding the 

 latter as distinct and identical with the species recently named and figured by 

 Dr. Stuxberg as StegocephaJns Kessleri, which form, in my opinion, belongs to 

 another genus, Aspidopleiirns, to be described in the sequel. 



Occurrence. — I have found the present species, not infrequently, in 

 several places off the coast of Norway, from the Christianiafjord to Vadso. 

 It is a true deep water form, occurring especially in great abundance in the 

 region of the deep sea corals, depth from 100 to 150 fathoms. 



Bisfrihution. — Arctic Ocean widely distributed: Greenland, Spits- 

 bergen, the Murman Coast, the White Sea, Franz Joseph's Land, the Kara 

 Sea, the Sibirian Polar Sea; Shetland Isles (Norman). 



