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are short. The joints are quite symmetrical, and are rather longer than the anal segment. Each 
furcal joint is twice as long as broad. The second inner setae on the left furcal joint is much 
longer and thicker than any of the others. 
The antennules are twenty-five-jointed and reach to the middle of the third abdominal 
segment. The last joint is equal to two-thirds of the length of the second last joint. 
The antennules, mandibles and maxillae are nearly similar to those of Heterorhabdus. 
The apical portion of the first maxillipedes is furnished with two very stout and moderately 
long spines. The inner surface of the spines is coarsely serrate (Plate XXXIX, fig. 18). 
The second maxillipedes are similar to those of Heterorhabdus. 
The exopodite and endopodite of the first, second, third and fourth pairs of swimming 
feet are three-jointed. 
The exopodite and endopodite of the fifth pair of feet are also three-jointed. The joints 
are short. The inner distal angle of the second joint of the exopodite is furnished with a 
short, stout spine. The spine is rather suddenly contracted in the distal portion. The inner 
margin of the first and second joints of the endopodite bears one moderately strong spine. 
The proximal portion of each spine is finely plumose. The distal portion is rather coarsely 
dentate (Plate XXXIX, fig. 21). 
Male unknown. 
_ This species is readily recognised by the truncate form of the last thoracic segment 
when viewed from above, by the proportional length of the segments of the abdomen, by 
the short symmetrical furcal joints, and by the armature of the two strong spines on the inner 
margin of the endopodite of the fifth pair of feet. 
Occurrence. — One specimen was obtained from the plankton collected with the 
HENSEN vertical net at Station 230, 2000 metres to the surface. 
Genus Disseta Giesbrecht, 1889. 
The members of this genus appear to be intermediate between Lwuczcutia and FHeteror- 
habdus. The various appendages shew a close relationship to those of Luczcutza. The biting 
edge of the mandible is almost identical in both types but it is quite distinct from Heterorhabdus. 
The furcal joints are asymmetrical and resemble those of Feterorhabdus. The left joint is 
longer and distinctly stouter than the right one. The male fifth pair of feet is quite distinct 
from that of the male of Luczcutza or Heterorhabdus. 
Two species were represented in the plankton collected by the ‘Siboga’. 
1. Disseta palumbot Giesbrecht. Plate XLI, figs. 11—21. 
Disseta palumboi Giesbrecht, 1889, p. 812. 
Disseta palumboi Giesbrecht, 1893, p. 369, pls. 29 & 38. 
Disseta palumbot Giesbrecht & Schmeil, 1898, p. 112. 
Fleterorhabdus grandis Wolfenden, 1904, p.. 120, pl. IX, fig. 36. 
Disseta palumboit Sars, 1905(d), p. 3- 
Heterorhabdus grandis Wolfenden, 1905, p. 8, pl. IV, figs. 7 & 8 (male). 
Fleterorhabdus grandis Pearson, 1906, p. 26. 
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