THYSANOPODA EGREGIA. 225 
The upper surface of the fourth and fifth abdominal segments show quite, 
as in the adults, feeble rudiments of three longitudinal keels, while the sixth 
segment has not yet obtained the flat dorsal excavation limited by feeble lateral 
earinae found in the adult.— The uropods are much shorter than the telson, a 
feature due to the young age of the specimen. 
Remarks.— That the specimen is a young of one of the species of Group b 
is certain. This group comprises hitherto only two species; judging from vari- 
ous particulars I think the specimen studied belongs to 7’. cornuta, not to T. 
egregia. It is, of course, possible, but in my opinion very improbable, that it 
belongs to an otherwise hitherto unknown species. 
10. Thysanopoda egregia H. J. Hansen. 
1905. Thysanopoda egregia H. J. HaNsEN, Bull. Mus. Océan. Monaco, no. 30, p. 22 (with two figures 
in the text). 
Sta. 4722. Jan. 16,1905. Lat. 9°31’S., long. 106° 30.5’ W. 300 fms. tosurface. 1 specimen. 
Remarks.— The single specimen measures 27 mm. in length; it is a female 
and, judging from its size, probably immature, as the single other specimen 
hitherto known, the male in the Monaco collection, is 44 mm. long. It agrees 
on the whole with the description in the Monaco paper, excepting that the third 
antennular joint is slightly tapering in breadth towards the end and the lower 
flagellum simple, while in the male figured that peduncular joint is slightly 
thickened towards the end and the basal part of the lower flagellum much 
thickened and furnished with a thick tuft of thin setae. Seen from the side, 
the upper margin of the carapace between the dorsal organ and the front end 
is more convex, being towards the front end curved more downwards, than in 
the Monaco specimen. 
Two other points may be mentioned. In the Monaco specimen a straight 
furrow runs along the side of the carapace considerably above the margin from 
the posterior margin to a little behind the cervical groove, and the upper margin 
of that furrow is raised and thickened so much that it looks like as a keel; in 
the smaller Agassiz specimen the furrow is scarcely distinct but the keel very 
conspicuous. In the description of the Monaco specimen I stated that the 
fourth to sixth abdominal segments have a dorsal keel along the posterior part 
of the median line of each, but there is no median keel on the sixth segment; 
the passage alluded to is correct as to the other particulars. 
Distribution.— The single specimen previously known was captured at 
Lat. 30° 41’ N., long. 17° 46’ W., 2500 to 0 m. 
