138 



It ought, evidently however, in my opinion to be considered as specifically distinct, 

 as it differs conspicuously not only in the more slender form of the body and 

 the far less expanded cephalic segment, but also in some of the structural details. 

 Thus the inner ramus of the 3rd pair of legs is distinctly 3-articulate, whereas 

 in the type species it is composed of only 2 joints; and the 4th pair of legs, 

 which in P. Richardi is wholly absent, is represented by a well-marked, though 

 very small rudiment. Finally, the distal joint of the inner ramus in the 1st pair 

 of legs has 2 setse more than in P. Richardi. 



Occurrence. Two or three female specimens of this form were collected, 

 many years ago, at Kval0, on the Nordland coast, from a depth of 40 50 fathoms. 



Distribution. Arctic Sea, off Spitsbergen and Nova j a Zemlia (Scott). 



Gen. 35. Cancerllla, Dalyell, 1851. 



Syn: Caligidium, Claiis (male). 



Generic Characters. Form of body very dissimilar in the two sexes, 

 being exceedingly short and stout in female, in male much more slender. 

 Cephalic segment in female greatly inflated, in male sub-depressed; rostral pro- 

 jection in both sexes obsolete. The succeeding segment well marked, with the 

 epimeral parts less distinctly defined in female than in male ; the 3 remaining 

 trunk-segments in both sexes imperfectly developed, without any epimeral plates. 

 Tail in female very short and composed of only 3 segments, in male more pro- 

 duced and 5 articulate. Caudal rami smaller in female than in male. Anterior 

 antennae in female comparatively short, with the number of joints considerably 

 reduced ; those in male not at all hinged, but of larger size and composed of a 

 greater number of joints, being moreover provided with numerous recurved sensory 

 filaments. Posterior antennae in both sexes distinctly prehensile, terminating in 

 a strong claw, outer ramus absent. Siphon faintly indicated by a slight pro- 

 longation of the lips, and turned anteriorly. Mandibles with the extremity slightly 

 dilated and indistinctly denticulated. Maxillce with only a single lobe turned 

 inwards. Both pairs of maxillipeds short and stout, especially in female. 4th 

 pair of legs absent in both sexes. All the remaining legs in female reduced, and 

 unfit for swimming; the 2 anterior pairs in male natatory, 1st pair smaller and 

 less perfectly developed than 2nd, which are quite normal, with both rami 

 3-articulate. Last pair of legs in both sexes small, uniarticulate, 



