86 G. 0. SARS. CRUSTACEA. [norw. pol. exp. 



with only 4 plumose setae. The 2 setiferous lobes usually present between 

 the masticatory lobe and the palp, are replaced by a simple conical projection, 

 tipped with a single seta. The basal joint of the palp is comparatively small, 

 but well defined, and carries only a single very small seta on a conical pro- 

 jection of the inner edge. The inner ramus is exceedingly minute, knob-like, 

 and carries on the tip 4 likewise small setse. The outer ramus, on the other 

 hand, is very powerfully developed, forming a cylindrical joint fully as long 

 as the remaining part of the maxilla, and tipped with 5 exceedingly long 

 plumose setae. 



The anterior maxillipeds (PI. XXV, fig. 1) are enormously developed, 

 considerably larger even than in the preceding species. They each form a 

 very strong curved stem apparently composed of 5 or 6 joints of very unequal 

 length, the 1st being, as usual, much the largest. Of the usual 5 digitiform 

 lobes, only the outer 2 are distinctly developed, the 3 proximal ones being 

 more or less rudimentary, the 2nd even replaced by a single very small seta. 

 The penultimate lobe carries 2 claw-like spines and a seta, and from the tip 

 of the very slender ultimate lobe an exceedingly long and falcate claw origi- 

 nates, accompanied by a very small seta. Another claw-like spine of about the 

 same size issues from the extremity of the maxilliped, lying in close prox 

 imity to the former. All these spines exhibit along the inner concave edge 

 a very dense ciliation (see fig. 2). In structure these maxillipeds differ con- 

 spicuously both from the type species and from H. norvegica, whereas they 

 closely agree with those of H. vipera, as figured by Dr. Giesbrecht. 



The posterior maxillipeds (fig. 3) are scarcely as long as the anterior, 

 and are far less powerful. They resemble in structure those in H. norvegica, 

 differing, however, conspicuously in the absence of the long, flexuous spine of 

 the 1st basal joint, this spine being here replaced by quite an ordinary seta. 



The legs (figs. 4—8) are also, on the whole, built upon the very same 

 type as in that species. They are all natatory and very powerfully developed, 

 though the 1st and last pairs are rather smaller than the 3 middle pairs. 

 In the 1st pair (fig. 4) the difference in size between the 2 rami is less pro- 

 nounced than in the other pairs, the inner ramus being scarcely shorter 

 than the outer, but fully as broad. This ramus carries, in all, 8 natatory 

 setae, one on the 1st, 2 on the 2nd, and 5 on the last joint. The outer 

 ramus has the terminal joint shorter than the other 2 combined, and provided 



