/ .1 



between the genital opening and the posterior margin of the segment, is greater than in 

 Paraeuchacta barbata. The secoiul and third segments are of about equal length. The anal 

 segment is about one-fourth of the length of the third segment. The furcal joints are rather 

 longer than broad, and are equal to the length of the anal segment. The appendicular seta is 

 longer than any of the others. 



The antennules extend to about the middle of the eenital segment. 



The antennae, mandibles, maxillae and maxillipedes are nearly similar to those of Para- 

 euchaeta barbata. 



The first pair of feet is similar to that of Paraeuchaeta barbata. The exopodite,is in- 

 distinctly three-jointed, and the outer-edge spine at the incomplete separation of the first and 

 second joints is very small. 



The outer-edge spine on the second joint of the exopodite of the second pair of feet, 

 extends to midway between the base and the apex of the first outer-edge spine on the third 

 joint. The second outer-edge spine on the third joint is short, and does not nearly reach the 

 base of the third outer-edge spine. 



The third and fourth pairs of feet are nearly similar to those of Paraeuchaeta barbata. 



Male unknown. 



This species is easily recognised by its long slender abdomen, and by the distance between 

 the genital opening and the posterior margin of the segment. 



O ecu r ren c e. — This species was found in plankton collected with the Hensen vertical 

 net at the following stations. 



Stat. 230 (2000 metres to surface), 2 specimens. — Stat. 276 (750 metres to surface), 1 specimen. 



7. Paraeuchaeta sibogac nov. sp. Plate XVI, figs. 1 — 9. 



Female — length 5 mm. 



Yiewed from above, the body appears moderately robust. The head is much contracted 

 in the middle, and is distinctly separated from the first thoracic segment. The last thoracic 

 segment is asymmetrical. The left posterior margin of the segment is more produced than the 

 right. Seen from the side, the posterior margin of the last thoracic segment appears angular 

 in outline. The rostrum is comparatively small and is directed downwards. The epistome is 

 hirsute, and a tuft of hairs is present on the last thoracic segment. 



The abdomen is short. The combined length of the abdomen and furca is equal to 

 rather less than one-half of the total length of the cephalotJiorax, from the frontal prominence 

 to the base of the genital segment. The genital segment is nearly as long as the combined 

 length of the next two segments. Viewed from above, the segment appears slightly asymmetrical, 

 and the process on each side of the genital opening can be seen projecting beyond the lateral 

 margins. In side view, the segment appears considerably swollen. The genital opening is flanked 

 by anteriorly directed tubercles. The tubercle on the right side is larger than the one on the 

 left. The second abdominal segment is nearly as long as the combined length of the third and 

 fourth segments. The anal segment is very small, and is only one-third of the length of the 





73 



SIBOÜA-EXPEDITIE XXIXö. 



