i6S 



The two sexes can readily be distinguished by the structure of the fifth pairs of feet, 

 and by the shape of the abdominal segments. 



Labidocera minuta has been recorded from the Indian and Pacific Oceans, and from the 

 Red Sea. 



6. Labidocera bataviac nov. sp. Plate L, figs. i — 8. 



Female — length 2,3 mm. 



Viewed from above, the body appears broadly ovate. The greatest width lies in the middle 

 of the first thoracic segment. The width is contained nearly two and one-half times in the 

 total length. The cephalic segment is without side hooks. The last thoracic segment is symmetrical. 

 The lateral margins are produced posteriorly into short divergent points. The basal part of the 

 rostrum is wide. The excavation is concave but it is very shallow. The rami are distinctly 

 articulated to the base (Plate L, fig. 2). 



The abdomen is very short. It is composed ot two segments. The combined length of the 

 abdomen and furca is contained fully six times in the total length of the cep halothorax, from 

 the frontal margin to the base of the genital segment. The genital segment is asymmetrical. 

 It is comparatively large, and the distal end, when seen from above, is unequally dilated. The 

 furcal joints are asymmetrical. The lelt furcal joint is one and a half times broader than long. 

 It has the appearance of being set at right angles to the abdomen, and its setae placed on 

 the inner margin. The setae are borne on the side and apex, however, as in the other members 

 of the genus. The right furcal joint is practically normal. It is one and a half times longer 

 than broad (Plate L, fig. 1). 



The antennules are twentv-three-jointed and extend to the end of the last thoracic segment. 



The antennae, mandibles, maxillae and maxillipedes are nearly similar to those of 

 Labidocera laevideniata. The apical portion of the second maxillipedes is composed of four joints. 



The endopodites of the first four pairs of feet are two-jointed. The exopodites are 

 three-jointed. 



The fifth pair of feet is slightly asymmetrical. The left exopodite is rather longer than 

 the right exopodite. The outer margin is furnished with two spines. The apex terminates in three 

 unequal spines. The endopodite is small, and is slightly bifurcate at the apex (Plate L, fig. 5). 



Male — length 1,96 mm. 



The male has a general resemblance to the female, but the abdomen is composed of 

 five segments. The furcal joints are broad and symmetrical (Plate L, fig. 6). 



The middle joints of the right antennule are considerably inflated. The upper margin of 

 the two proximal hinge joints, and of the distal hinge joint is armed with fine teeth (Plate L, fig. 7). 



The thumb-like process at the proximal end of the outer margin of the first joint of the 

 exopodite of the right fifth foot is long and stout. There is a distinct tooth-like spine close to 

 the base of the thumb. The middle of the outer margin is furnished with a low broad tooth. 

 The claw-like second joint has a distinct tooth on the middle of the outer margin. The terminal 

 joint of the left exopodite is about twice as long as broad. It is provided with one outer edge, 

 and three apical spines. The inner margin has a pad of fine hairs (Plate L, fig. 8). 



168 



