104 G. O. SARS. CRUSTACEA. [NORW. POL. EXP. 



The 1st pair of legs (fig. 7) are comparatively small, and also differ in 

 other respects from the 3 succeeding pairs. The 1st basal joint has its usual 

 plumose seta inside, and at the inner corner of the 2nd basal joint another 

 deflexed seta occurs, not found in the other pairs. The outer ramus is some- 

 what longer than the basal part, and has the first 2 joints rather broad, each 

 carrying inside a natatory seta, but without any trace of spines outside. The 

 last joint is somewhat shorter than the other 2 combined, and is rather nar- 

 rower, ^having likewise the outer edge unarmed; it carries 4 natatory setse 

 inside, and at the tip a slender spine, outside which another much smaller 

 spine is attached. The inner ramus is scarcely more than half as long as 

 the outer, and is composed of only 2 joints, the last of which is the larger. 

 It carries 5 natatory setae, none of which issue from the outer edge. 



The 3 succeeding pairs (figs. 8, 9, 10) are essentially of similar structure, 

 and much larger than the 1st, with both rami distinctly 3-articulate, and the 

 outer one very strongly developed, being more than twice as large as the 

 inner. In all the 3 pairs the terminal joint of this ramus is longer than the 

 other 2 combined, and is armed outside with 3 short spines, inside with 5 

 natatory set, and at the tip with a long spine coarsely denticulate outside. 

 The inner ramus has likewise the last joint considerably larger than the 

 others, and in all 3 pairs carries 10 natatory setee, 2 of which issue outside 

 the last joint. On a closer comparison, however, some minor differences are 

 found to exist between these 3 pairs. Thus in the 2nd pair (fig. 8), the 

 natatory seta of the 1st joint of the outer ramus is replaced by a short spine, 

 and in the 3rd pair (fig. 9) a very strong deflexed spine occurs at the outer 

 corner of the 2nd basal joint, not found in the 2nd pair. In the 4th pair 

 (fig. 10) a similar, but much shorter spine is present, whereas the 1st basal 

 joint is without the usual plumose seta inside. 



The last pair of legs (fig. 11) are very different from the others, each 

 forming a simple stem composed of 3 joints, of which the first 2 represent 

 the basal part, the 3rd the outer ramus. The latter is very slender and 

 elongated, almost twice as long as the other 2 combined, and linear in form, 

 carrying at the tip 2 unequal spines, the inner one the longer and somewhat 

 incurved. Otherwise these legs are quite naked. 



The adult male (PI. XXX, fig. 3) is somewhat smaller than the female, 

 scarcely exceeding a length of 1*05 mm. 



