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third segment. The furcal joints are longer than broad, and are nearly twice as long as the 

 anal segment. The appendicular seta on the furcal joints is much longer than any of the others. 



The antennules reach to the middle of the genital segment. 



The antennae, mandibles, maxillae and maxillipedes are somewhat similar to those of 

 Paraeuchaeta barbata. 



The exopodite of the first pair of feet is indistinctly three-jointed. The outer-edge spine 

 at the incomplete separation of the first and second joints is moderately long, and extends to 

 near the end of the combined joint. 



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

 is considerably longer than any of the other outer-edge spines. It extends to the apex of the 

 first outer-edge spine on the third joint. The second outer-edge spine on the third joint extends 

 half way along the margin, towards the base of the third outer-edge spine. 



The third and fourth pairs of feet resemble those of Paraeuchaeta barbata. 



Male unknown. 



Paraeuchaeta sibogae is easily distinguished from the other members of the genus, by 

 the asymmetrical and slightly angular posterior margins of the last thoracic segment, and by 

 the very swollen genital segment with its pair of strong tubercles as seen in side view. 



Occurrence. — Five specimens were found in the plankton collected with the Hensen 

 vertical net at the following stations. 



Stat. 128 (700 metres to surface), 1 specimen. — Stat. 148 (1000 metres to surface), 1 spe- 

 cimen. — Stat. 230 (2000 metres to surface), 2 specimens. — Stat. 243 (1000 metres to 

 surface), 1 specimen. 



8. Paraeuchaeta weberi nov. sp. Plate XV, figs. 9 — 16. 



Female — length 8,5 mm. 



Viewed from above, the body appears elongate and moderately robust. The head is 

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

 thoracic segment is symmetrical and slightly pointed. Viewed from the side, the last thoracic 

 segment is seen to be triangular in outline, and terminates in a small, but quite distinct point. 

 The rostrum is moderately large and is directed forward. The epistome is hirsute, but the last 

 thoracic segment has no tuft of hairs. 



The abdomen is short. The combined length of the abdomen and furca is distinctly 

 less than one-half of the total length of the ccphalothorax, from the frontal process to the base 

 of the genital segment. The genital segment is rather shorter than the combined length of 

 the second and third segments. Viewed from above, the genital segment appears quite asym- 

 metrical. The segment is considerably swollen at the posterior end, but the left side is more 

 inflated than the right. The middle of the segment is traversed by a deep constriction which 

 is slightly obscured by an overlapping of the anterior half of the segment. The overlapping 

 part terminates in two small tubercles. When seen from the side the genital segment has a 

 most remarkable appearance, due to the constriction on the dorsal surface, and to the pair of 

 large oval processes that guard the genital opening. The second abdominal segment is rather 



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