237 
4. Monstrilla inserta nov. sp. Plate LVI, figs. 7 and 8. 
Female — length 3,4 mm. 
Seen from above, the body appears moderately 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. Its 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 LVI, fig. 7). 
The antennules are three-jointed and are equal to one-third of the length of the 
cephalic segment. 
The fifth 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 fifth pair of feet. The chief difference is in the inner lobe of the fifth pair. 
GIESBRECHT’s figure shews the inner lobe of the fifth pair of MWonstrilla grandis to be furnished 
with two setae, instead of one in the ‘Siboga’ specimens. 
Occurrence. — 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 to. 
Female — length 3 mm. 
Seen from above, the body appears rather slender. The cephalic segment is conside- 
tably contracted in front and is inflated 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. Its 
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 bi-lobed. The inner lobe is 
BSe 
