THYSANOPUDA EGIIEGIA. 225 



The upper surface of the fnvu'th 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 

 carinae 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 Ciroup b 

 is certain. This group comi:)rises hitherto onh' two species; judging from vari- 

 ous particulars I think the si)ecimen stutlied belongs to T. coniulu, not to T. 

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

 belongs to an otherwise hitherto unknown species. 



10. Thysanopoda egregia 11. J. H.^nsen. 



1905. Thysanopoda egregia H. J. Hansen, Bull. Mus. Ocean. iSIonaco, 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 lengtli; it is a female 

 and, judging from its size, i)rol)al)ly 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 slightl}' 

 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, Iseing towards the front end cm'\'ed 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 descriiition 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° 4()' W., 2500 to m. 



