i8 5 



second joint of the left basiopodite apparently does not possess the strong spine that is 

 present in the 'Siboga' male, and no reference is made to the long outer edge spine on the 

 second joint of the exopodite of the second pair of feet. 



Occurrence. - Two females and one male were obtained from the plankton collected 

 with the Hensen vertical net at Station 143, 1000 metres to the surface. 



Genus Neopontella nov. 



This genus is very closely related to Parapontella, and at first sight I was inclined to 

 regard its representative to be a trne member of that genus. A closer examination of the two 

 sexes, however, shewed that it is clearly distinct. 



The generic differences between this genus and Parapontella, are in the structure of 

 the fifth pair of feet of the female, and in the segmentation of the abdomen of the male. 



The female fifth pair of feet has no tracé of an endopodite. The abdomen of the male 

 is composed of four segments. 



The antennules, antennae, mandibles, maxillae and maxillipedes are almost identical 

 with those of Parapontella brevicornis (Lubbock). The four pairs of swimming feet are also 

 similar to those of that species. 



One species belonging to this new genus was obtained from the plankton collected 

 during the traverse of the 'Siboga'. 



1. Neopontella typica nov. sp. Plate LV, figs. 1 — 15. 



Female — length 1,13 mm. 



Seen from above, the body appears elongate ovate in outline. The greatest width is 

 in the middle. The width is contained two and a half times in the total length of the body. 

 The head is distinctly separated from the first thoracic segment. The frontal margin is rather 

 broadly rounded. The fourth and fifth thoracic segments are completely fused. The last thoracic 

 segment is very slightly produced. The posterior margin of the segment is narrowly rounded. 

 Viewed from the side, the apex of the last thoracic segment is seen to be evenly and rather 

 bluntly rounded. The rostrum is almost similar to that of Parapontella brevicornis, but the 

 filaments appear to be rather shorter (Plate LV, fig. 3). 



The abdomen is composed of three segments. The combined length of the abdomen 

 and furca is contained fully twice in the total length of the cep halothorax, from the frontal 

 margin to the base of the genital segment. The genital segment is considerably swollen. It is 

 nearly equal to the combined length of the next two segments. Seen from the side, the segment 

 appears greatly inflated in the region of the genital opening. The second and third segments 

 are of nearly equal length. The second segment is not armed with spines. The furcal joints 

 are nearly twice as long as broad, and are almost as long as the anal segment (Plate LV, 

 figs. 1 and 2). 



The antennules are composed of eighteen joints. The third and fourth joints are very 

 small. The last joint is indistinctly segmented at the distal end. 



185 



SIEOGA-EXPED1TIE XXIXtf. 24 



