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transparent. The antennules are short and seven-jointed. The antennae, mandibles, maxillae and 

 maxillipedes are similar to those of Altcutha 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 tracé of segmentation to indicate a proximal and distal joint. 



This genus is closely related to Alteutha 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. 



i. Alteuthella pellitcida nov. sp. Plate LXYI, 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 bas no tracé 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 

 (Plate 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-EXPEUITIE XXIXa. 27 



