151 



broad; the solid chitine forms a somewhat irregularl}' shaped plate (fi<^. la), in wliich a 

 tolerably lar-ge area of the anterior third part is thin-skinned and partly merging in the 

 skin surronnding the plate (though in two dissected specimens the shape of the plate and of 

 the membranous pait were somewhat different, the present description will do for- both). 

 The genital apertures are seen far to the front on the posterior half of the plate; they ai-e 

 stiongly t'urved and situated at a moderately long or rather short distance from each other, 

 in such a position that their muscles turn very much sideways and a trifle forward. The 

 space between the genital apertures has some longitudinal stripes of very short hairs; the 

 i-emaindei- of the area is naked. At a short distance behind the apertures appear a couple 

 of small cones, which doubtless are the rudimentary caudal stylets. 



MALE. A good-sized specimen is -55 mm. long and 42 mm. broad, which is large 

 indeed, though, considering the proportion between the sexes in otlier species, it is but 

 middle-sized (fig. 3b : fig. 3a) comparatively to the females, which are large. Seen from below, 

 its shape is very characteristic, almost hexagonal, the posterior margin of the tinnk forming 

 a somewhat convex line, its lateral outline being moderately long and somewhat concave, 

 wheieas the head has a long, slightly curved, lateral outline and a very short anterior 

 margin. The head nearly the size of the trunk. The frontal border strongly produced, 

 with converging lateral margins; terminal margin short, cut otf in a sti'aight line, with a 

 pretty deep incision in its median part, while distally each lateral margin has two deej) and 

 rather broad incisions and, somewhat in front of the antennula, a slight depression; these 

 incisions form tlu-ee pairs of lobes, the hindmost of which are low, the others good-sized with 

 almost right angles; the terminal margin of all the lobes is furnished with a row of nume- 

 rous minute processes. AntenniUae short, 2-jointed, with short setae. Antennae of scarcely 

 medium size, 3-jointed, second joint the longest; terminal seta the length of the last joint. 

 Mouth-border a little broader than in the female; maxillulae as in the female. Maxillte 

 (fig. 1 b) nearly as in the female, and the two last joints coalescent as in the other sex. 

 Maxillipeds of medium length, basal joint rather slender, otherwise tliis joint as well as the 

 others constructed and equipped (fig. 3 f and fig. 3 h) as in the female. The sub-median 

 skeleton has the two first pairs of processes, first pair about middle-sized, second pair power- 

 fid, long and diverging slightly backward. The lateral border of the head has a peculiar 

 shape, curving strongly towards the base of the maxillae, then turning backward and obliquely 

 sideways almost at right angles; the margin fringed in the middle with moderately long 

 hairs, anteriorly and posteriorly with long hairs, and from its hindmost end a narrow stripe 

 of extremely long hairs runs upward across the side of the animal, where it curves slightly 

 forward (fig. 3g), then continues across the back in an oblique line. Beliiud this stripe the 

 back and sides, as well as the ventral surface of the trunk, are densely covered with mode- 

 rately long, and in front of the second pair of legs, with loug hairs. About the middle of 

 the back of the trunk is seen a short and very narrow transverse area. First pair of trunk- 

 legs pretty small, their basal part indistinctly defined, and from this part proceed two 



