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and maxillipedes, and in the structure of the five pairs of feet. The abdomen of the female 

 is only two-jointed and each furcal joint is furnished with three setae. 



The genus was represented in the 'Siboga' collections by two apparently undescribed species. 



1. Thaumalcus (ntllatus nov. sp. Plate LYIII, figs. 7 and 8. 



Male — length 1,7 mm. 



Seen from above, the body appears elongate and is rather slender. The cephalic segment 

 is considerably inflated at the distal end. It is distinctly shorter than the posterior part of the 

 body. The frontal margin is broad and rounded with a distinct protuberance in the middle. 



The abdomen is composed of three segments. The second segment is shorter and the 

 anal segment is longer than the others. The distal end of the anal segment is expanded. The 

 furcal joints are short and broad. Each joint is furnished with four apical setae that are 

 distinctly swollen at the base (Plate LVIII, fig. 7). 



The antennules are five-jointed, prehensile, and equal to three-fifths of the length of 

 the cephalic segment. 



The fifth pair of feet is rudimentary and without setae (Plate LVIII, fig. 8). 



This form does not agree with any of the known mal es belonging to the genus. It 

 can readily be recognised by the proportional length of the abdominal segments, and by the 

 swollen base of each seta on the furcal joints. 



Occurrence. - Thirty specimens were obtained from the plankton collected at Station 

 142, off Laiwui, Paternoster Islands. 



2. Thaumaleus gigas nov. sp. Plate LVIII, figs. 9 and 10. 



Female — length 8 mm. 



Seen from above, the body appears very elongate and is rather slender. The cephalic 

 segment is very long. It is two and one-third times longer than the posterior end of the animal. 

 The segment is contracted in front and is much inflated behind. The frontal margin is narrow 

 and is slightly concave. 



The abdomen is composed of two segments. The genital segment is sub-quadrangular 

 in shape. The margins slope inwards from the middle to the distal end. The segment is slightly 

 longer than the anal segment and is traversed by a distinct suture. The anal segment is 

 rather shorter than the genital segment. It is very narrow in front and is much expanded at 

 the posterior end. The furcal joints are nearly as long as the anal segment. Each joint is 

 furnished with one marginal seta and two apical setae (Plate LVIII, fig. 9). 



The antennules are comparatively short and four-jointed, and equal to about one-sixth 

 of the length of the cephalic segment. 



The fifth pair of feet is moderately broad. The apex is bi-lobed. The inner lobe is rather 

 broad but does not extend beyond the apex of the outer lobe. It is without setae. The outer 

 lobe is furnished with three moderately long setae (Plate LVIII, fig. 10). 



This species can readily be separated from the other members of the genus by the 



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