2 JO 



furcal joints is contained nearly twice in the total length of the cephalothorax, from the frontal 

 maro-in to the distal end of the fifth thoracic segment. The genital segment is moderately 

 lonor a nd is considerably inflated at the proximal end. It is equal to the combined length of 

 the next three segments added to half the length of the furcal joints. The second and fourth 

 segments are sub-equal in length. The third segment is equal to two-thirds of the length of 

 the second segment. The furcal joints are slightly longer than the anal segment. The joints 

 are furnished with two outer marginal setae and three apical setae (Plate LXIX, fig. i). 



The antenhules are rather long and seven-jointed. The joints are all of moderate length, 

 except the first and third, which are shorter than the others. (Plate LXIX, fig. 2). 



The antennae are short, stout and four-jointed. The apex of the fourth joint is furnished 

 with two stout curved claws and four setae (Plate LXIX, fig. 3). 



The apex of the mandible is stylet-shaped. The basal portion is of moderate size, but 

 it is deeply constricted in the middle. The upper margin is finely serrate (Plate LXIX, fig. 4). 



The maxillae are short and broad. They are furnished with one marginal and three 

 apical setae. 



The apex of the first pair of maxillipedes is stylet-shaped. The upper margin is coarsely 

 serrate (Plate LXIX, fig. 5). 



The second pair of maxillipedes is small and two-jointed. The second joint terminates 

 in one very stout claw. The upper surface is provided with two short spines (Plate LXIX, fig. 6). 



The exopodites and endopodites of the first three pairs of feet are three-jointed. The 

 exopodite of the fourth pair of feet is three-jointed. The endopodite is one-jointed. The outer 

 margin is sharply constricted in the middle. The apex is furnished with two moderately long 

 spathulate spines (Plate LXIX, fig. 7). 



The fifth pair of feet is slender and of moderate length. The apex of each foot bears 

 two short spines. 



Male unknown. 



This species is readily recognised by the elongate body, by the moderately long and 

 inflated genital segment, and by the proportional length of the joints of the antennules. 



Occurrence. -- Two specimens were obtained from the plankton collected during the 

 night at Station 142, when the 'Siboga' was anchored off Lawui, on the Coast of Obi Major. 



4. P seudanthessius obscurus nov. sp. Plate LXIX, figs. 8 — 14. 



Female — length 1,15 mm. 



Seen from above, the body appears elongate and narrowly ovate. The frontal margin 

 is narrowly rounded. It is almost angular in outline. The fourth thoracic segment is short and 

 is very slightly produced posteriorly. The distal ends are rounded. The fifth thoracic segment 

 is broadly triangular in shape with the distal end moderately expanded. 



The abdomen is slender and is composed of four segments. The combined length of 

 the abdomen and furcal joints is contained one and two-third times in the total length of the 

 cephalothorax, from the frontal margin to the distal end of the fifth thoracic segment. The 



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