145 
fig. 13). The second and third segments are of about equal length. The anal segment is equal 
to two-thirds of the length of the third segment. The furcal joints are one and a half times 
longer than broad. They are slightly longer than the third abdominal segment. The second 
and third inner setae are each furnished with a dense tuft of dark coloured hairs. The ova are 
few in number and are very large. 
The antennules are composed of twenty joints and are of nearly equal length. The 
left antennule extends to the end of the fourth abdominal segment. The terminal joint of the 
tight antennule only is furnished with two densely plumose setae (Plate XLIII, fig. 14). 
The antennae, mandibles, maxillae and maxillipedes are somewhat similar to those of 
Arvetellus setosus. 
The first four pairs of feet are also similar to those of that species. 
The fifth pair is slightly asymmetrical. Each foot consists of a single joint. There is no 
distinctly defined basal part. The proximal portion of the outer margin is furnished with a 
moderately long seta. The setae on the right foot is longer than the one on the left foot. 
The distal portion of the outer margin bears two very small hairs. The apex is furnished with 
one long plumose seta (Plate XLIII, fig. 16). 
Male — length 3,37 mm. ; 
The male resembles the female in general appearance, but the abdomen is composed 
of five segments. The first and third segments are larger, and the second is smaller than the 
others. The fourth and fifth segments are of about equal length. 
The left antennule is modified for grasping. It is composed of eighteen joints. The 
eleventh, twelfth and thirteenth joints are distinctly enlarged. The fifteenth, sixteenth and 
seventeenth joints are furnished on the upper edge with a narrow hyaline plate. The hinge is 
situated between the sixteenth and seventeenth joints (Plate XLIII, fig. 18). 
The mouth organs and swimming feet are nearly similar to those of the female. The 
inner margin of the second joint of the endopodite of the antennae is furnished with a long 
seta (Plate XLIII, fig. 15), which appears to be entirely absent in the female. 
The fifth pair is large and prehensile. The second joint of the right exopodite is lamelliform. 
It is much dilated at the middle. The apex is narrow and sinuous. The inner margin of the 
joint is distinctly notched. The second joint of the left exopodite is broadly triangular in outline. 
It is well supplied with muscles. The apex of the joint bears two moderately long curved spines. 
The spines are rather shorter than the joint. The distal end of the inner spine is sickle-shaped. 
The apex of this spine is distinctly bifurcate (Plate XLIII, fig. 19). 
This species appears to come very close to WOLFENDEN’s type species (Paraugaptilus 
6uchanz) and I was inclined at first to regard it as identical. Dr. WoLFENDEN, to whom I 
submitted copies of the figures now given, is of the opinion, however, that it is distinct. The 
fifth pair of the female of the present form differs from WOLFENDEN’s species, in having two 
small outer edge hairs near the distal end of the joint. The male of the genus has hitherto 
been unknown. 
Occurrence. — Males and females were found in the plankton collected at the 
following stations. 
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SIBOGA-EXPEDITIE XXIX@. 19 
