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This species approaches Labidoccra ncrii (Kroyer) in general appearance, but the structure 

 of the fifth pair of both sexes readily separates it from that form, and from any of the other 

 known members of the genus. 



The name is derived from Madura Strait, where the series of investigations in the 

 Malay Archipelago carried out by this expedition began, and finally ended, after a year of 

 exploring the seas and straits in the area. 



Occurrence. — One hundred and sixty females and four males vvere obtained from 

 the plankton collected at the following stations. 



Stat. 16, So specimens. — Stat. 141 (HENSEN vertical net, 1500 metres to surface), 60 spe- 

 cimens. — Stats. 194 — 7, 5 specimens. — Stat. 203 (surface), 13 specimens. — Stat. 203 

 (HENSEN vertical net, 1500 metres to surface), 2 specimens. — Stat. 2S2, 2 specimens. — 

 Stat. 315, 2 specimens. 



Genus Pontellopsis Brady, 1883. 



The members of this genus are separated from Pontclla and Labidoccra by the complete 

 absence of dorsal and rostral lenses, and by the long slender rami of the rostrum. The structure 

 of the fifth pair of feet of the two sexes is something similar to that found in Pontella. The 

 endopodite of the first pair of feet is three-jointed. 



Eight species of Pontellopsis were obtained from the plankton collected by the 'Siboga'. 

 Two of the species do not appear to have previously been described. 



1 . Pontellopsis armata (Giesbrecht). 



Monops armatus Giesbrecht, 1889, p. 28 



Monops armatus Giesbrecht, 1893, p. 487, pis. 26 & 41. 



Pontellopsis armata Giesbrecht & Schmeil, 1898, p. 148. 



Monops armatus Cleve, 1901, p. 7. 



Pontellopsis armata Thompson & Scott, 1903, p. 253. 



Pontellopsis armata Wolfenden, 1905(0), p. 1022, pi. XCIX. 



This species proved to be the most abundant and generally distributed member of the 

 genus, as shewn by the records of its occurrence. 



Stat. 35. — Stat. 89. ■ — Stat. 98, 23 females and 17 males. — Stat. 117', 1 specimen. — 

 Stat. 124, 8 specimens. — Stat. 138, 1 specimen. — Stat. 143 (HENSEN vertical net, 1000 

 metres to surface), 1 specimen. — Stat. 144. — Stat. 157, 2 specimens. — Stat. 184. — 

 Stat. 186, 1 specimen. — Stat. 189', 3 specimens. — Stat. 193, 1 specimen. — Stats. 

 194 — 7, 2 specimens. — Stat. 203 (surface), 9 specimens. — Stat. 213, 20 specimens. — 

 Stat. 2 1 5 a , 2 specimens. — Stat. 216, 2 specimens. — Stat. 217 (surface), 2 specimens. — 

 Stat. 217 (horizontal cylinder), 2 specimens. — Stat. 222, 3 specimens. — Stat. 223, 2 spe- 

 cimens. — Stat. 229, 15 specimens. — Stat. 245, 1 specimen. 



The female of Pontellopsis armata can readily be recognised by the hirsute body, by 

 the elongate spiniform projections of the last thoracic segment, and by the structure of the 

 fifth pair of feet. 



This species has been recorded from the Indian and Pacific Oceans. 



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