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4. Monstrilla inserta nov. sp. Plate LVII, figs. 7 and S. 



bemale — length 3,4 mm. 



Seen from above, the body appears modcrately slender. The cephalic segment is evenly 

 rounded in the frontal portion and is very slightly contracted at the distal end. It is slightly 

 longer than the posterior part of the animal. The frontal margin is very narrowly rounded 

 and is slightly cleft. 



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

 in shape and is traversed by a distinct suture rather in front of the middle. lts length is equal 

 to twice the combined length of the next two segments. It is rather shorter than the united 

 length of the next two segments and furcal joints. The second and third segments are very 

 short and are of nearly equal length. The furcal joints are three times longer than the anal seg- 

 ment. Each joint is furnished with one outer marginal seta and five apical setae (Plate LVII, fig. 7). 



The antennules are three-jointed and are equal to one-third of the length of the 

 cephalic segment. 



The hfth pair of feet is rather slender and is distinctly bi-lobed. The inner lobe is 

 narrower than the outer lobe and does not extend beyond the end of it. The apex is furnished 

 with one seta. The outer lobe is furnished with three setae (Plate LVII, fig. 8). 



This species comes very near Monstrilla grandis in general appearance, and in the 

 shape of the hfth pair of feet. The chief difference is in the inner lobe of the fifth pair. 

 Gif.sbrecht's figure shews the inner lobe of the fifth pair of Monstrilla grandis to be furnished 

 with two setae, instead of one in the 'Siboga' specimens. 



O cc ur re nee. — Seven females were obtained from the plankton collected at the 

 following stations. 



Stat. 40, 2 specimens. — Stat. 66, 4 specimens. — Stat. 282, 1 specimen. 



5. Monstrilla cymbula nov. sp. Plate LVII, figs. 9 and 10. 



Female — length 3 mm. 



Seen from above, the body appears rather slender. The cephalic segment is conside- 

 rably contracted in front and is inrlated in the middle. It is slightly longer than the posterior 

 part of the animal. The frontal margin is sharply concave. 



The abdomen is composed of three segments. The genital segment is sub-cylindrical in 

 shape with a distinct constriction in the middle where it is traversed by a well defined suture. 

 It is one and a half times longer than the combined length of the next two segments. lts 

 length is rather shorter than the united length of the next two segments and furcal joints. 

 The second and third segments are sub-equal in length. The furcal joints are two and a half 

 times longer than the anal segment. Each joint is furnished with two outer marginal setae 

 and four apical setae (Plate LVII, fig. 9). 



The antennules are two-jointed and are equal to two-thirds of the length of the 

 cephalic segment. 



The fifth pair of feet is short and broad and is distinctly bidobed. The inner lobe is 



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