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transparent. The antennules are short and seven-jointed. The antennae, mandibles, maxillae and 
maxillipedes are similar to those of Alfewtha interrupta (Goodsir). The exopodite of the antennae 
is two-jointed. The mandible palp is two-branched. The exopodite is very much shorter than 
the endopodite. The terminal claw of the second pair of maxillipedes is shorter than the second 
joint. The first four pairs of feet are very slender. The exopodite and endopodite are three- 
jointed. The exopodite of the first pair of feet is prehensile. The third joint is very small 
and is furnished with a single curved claw. The fifth pair of feet is one-jointed and rather 
foliaceous. The fifth pair shews no trace of segmentation to indicate a proximal and distal joint. 
This genus is closely related to A/feutha Baird in general appearance, but its members 
can readily be separated by the seven-jointed antennules, by the single curved claw on the 
apex of the third joint of the exopodite of the first pair of feet, and by the absence of a 
division between the proximal and distal portions of the fifth pair of feet. 
Three species belonging to this genus were obtained from the material collected by the 
‘Siboga’ in the Malay Archipelago. 
1. Alteuthella pellucida nov. sp. Plate LXVI, figs. 13—20. 
Female — length .63 mm. 
Seen from above, the body appears short and depressed. It is broadly oval in outline 
and very transparent. The greatest width is at the distal end of the cephalic segment and is 
equal to two-thirds of the entire length of the animal. The cephalic segment is large and 
represents one-half of the length of the Copepod. The distal ends are slightly produced and 
pointed. The distal ends of the first three thoracic segments are also pointed. The rostrum is 
large and prominent. The frontal margin is broadly rounded (Plate LXVI, fig. 13). 
The abdomen is composed of four segments. The genital segment is very large and 
is somewhat quadrangular in outline. It has no trace of a suture on the dorsal surface. The 
lateral margins are produced posteriorly into well defined points. The second, third and fourth 
segments are short and narrow. The furcal joints are very short and broad. The apex of each 
segment is deeply notched, but there is no tooth on the outer angle (Plate LXVI, fig. 13 A). 
The antennules are short and seven-jointed. The last three joints are small. 
The antennae, mandibles, maxillae and first pair of maxillipedes are similar to those 
of Alteutha depressa Baird. 
The second pair of maxillipedes is rather slender. The second joint is moderately long 
and narrow. The terminal claw is short and curved. It is much shorter than the second joint 
(late LXVI, fig. 15). 
The first pair of feet is moderately slender. The third joint of the exopodite is small 
and is furnished with a short curved claw. The endopodite is three-jointed and is considerably 
shorter than the exopodite. The first and second joints have each one inner marginal seta. 
The apex of the third joint is furnished with three setae (Plate LXVI, fig. 16). . 
The exopodite and endopodite of the second, third and fourth pairs of feet are three- 
jointed and very slender. 
The fifth pair of feet is moderately wide at the base and contracts uniformly to a 
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SIBOGA-EXPEDITIE XXIX@. 27 
