240 



COPEPODA 



out and possesses 2 long Si. The maxillulae are fairly well developed, and different from those of the 

 male of X. borealis; the Le has 7 long powerful as well as 2 short bristles. The Li i is only a little 

 longer than wide, and has at least 9 bristles, which are long, broad, somewhat lamellous and distinctly 

 plumous; the Li 2 has 4 short setae, the Li 3 has 4 fairly long, partly plumous setae, and the third 

 basipodite has 5 setae. The endopodite seems only to possess 10 setae, and so does the exopodite. 

 The maxillae are rather soft-skinned ; the Lob. I has 4 rather slender setae, the lob. 2-3 have 3 each ; 

 the fourth lobe has 2 slender plumous bristles and a long, broad, strongly plumous seta, and the fifth 

 lobe has a single shorter one of similar structure in addition to 2 fairly strong plumous setae and a very 

 delicate one. The endopodite has 2 vermiform setae, 5 rather slender brush-shaped ones, and a curious 

 globular appendage scarcely twice as long as wide, with terminal almost circular opening and striated 

 wall. The maxillipeds are scarcely different from those of X. borealis. 



They?r^/ and second pairs of legs are scarcely different from those of X. borealis; the distal seg- 

 ments of the third and fourth legs are wanting, while the proximal ones are like those of mentioned 

 species. The fifth pair of legs extends distinctly beyond the end of the abdomen; the right leg is 

 comparatively short and somewhat convex outwards, but extends distinctly beyond the end of the 

 first basal segment (text-fig. 77 a, d); it consists, as seen in figure, of 4 segments, of which the last one 

 shows trace of further segmentation, and is terminated with a short tooth. The left leg consists of 

 three elongated proximal segments, the comparative length of which is seen in figure; the first seg- 

 ment has inwards on the anterior surface a short keel (text-fig. 77 a c). The fourth segment (Re II?) 

 is much shorter than the preceding ones, and is somewhat enlarged towards the middle, where a 

 process with two groups of about 10 bristles is found; beyond this process the segment is hollowed 

 with a concavity facing inwards, and has about 6 setae along the outer margin, as well as a tuft of 

 5 more slender ones and one stronger seta terminally (text-fig. 78b c); apparently articulated to this 

 segment a short "segment" with a tuft of hairs was found. The terminal segment (Re III?) has along 

 the one margin in the middle 5 fairly strong spines, and terminally a hooked spine ; at base of which 

 four moderately slender setae are observed. 



Occurrence. The Thor has collected a single male. 



/ 7 1904 St. 183 6i30 L. N. I7o8 L. W. Yt. 1800 M. Wire i f d 1 . 

 Distribution. A few males have once been taken '?/ 1908 5936 L. N. 7 L. W. Depth 1140 Meters. 



Remarks. As far as I am able to see the male of this species, which is especially characterized 

 by the curious development of the left foot, is identical with Scott's Amallophora claviger. The 

 somewhat lamiuous setae which are observed in the maxillulae and maxillae suggest some affinity to 

 X. Grenii; its much smaller size excludes this species. 



About 20 species of Xanthocalanus have been described; to refer the described male to most 

 of these may be excluded, especially on account of its much greater size (4-5 mm. against 23 mm. for 

 the female). Only X. pinguis Farr. (4-5 5-1 mm.), X. muticus G. O. Sars (5-3 mm.) and X. profimdus 

 G. O. Sars (6-2 mm.) could possibly be the females of this species. From X. pinguis it seems to be 

 distinguished by rounded lateral corners and longer antennulae. From X. profundus it seems to differ 

 in quite similar features, and from X. mutictts it seems to differ by longer rostrum, by lateral corners 



