THYSANOPODA EGREGIA. 225 



The upper surface of the fourth and fiftli 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 

 carinae found in the adult. — The m-opods 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 T. cornuta, not to T. 

 egregia. It is, of course, possible, but in my opinion very improbable, that it 

 belongs to an otherwise liitherto unknown species. 



10. Thysanopoda egregia H. J. Hansen. 



1905. Thysanopoda egregia H. J. Hansen, Bull. Mus. Ocdan. 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. to surface. 1 specimen. 



Remarks. — The single specimen measures 27 mm. in length; it is a female 

 and, judging from its size, probably immatm^e, 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 i.s 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 Uke as a keel; in 

 the smaller Agas.siz 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 alUided 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 m. 



