2 7 



ot unequal size, larger in the male than in the female. The ridge between the cervical groove 

 and the posterior margin carries, like in the Challenger types, in the male a doublé row of 

 acute teeth, curved forward, 14 or 15 on each side, of which the foremost and the last pair 

 are a little larger than the rest; in the female the _teeth of this ridge are smaller. The posterior 

 margin which appears somewhat less concave than in the Figure 1 of the Report on the 

 Challenger Macrura, is armed on its anterior edge with acute teeth, which gradually decrease 

 in size laterally. The armature of the lateral margin of the carapace is in the male 5 on the 



8 H 



left and 5 on the right side: in the female the formula is * at either side. In the Challeno-er 

 types the anterior division is armed with 10 or 12 spines, the central with 4 or 5, the posterior 

 with 25 or 26, so that they differ only by the number of spines on the anterior division. The 

 three or four last spines of the posterior division are sometimes considerably smaller than 

 the rest, so in the male on the left side, in the female on the right. The sublateral rido-e on 

 the branchial region carries as many teeth as the posterior division of the lateral margin, but 

 these teeth are considerably smaller; anteriorly this ridge runs parallel with the lateral margin, 

 soon, however, it curves inward so that, at one third of its length from the posterior extremity, 

 it is more than one and a half as far distant from the lateral margin than anteriorly; from 

 here it approaches again to the margin. The posterior edge of the cervical groove is also beset 

 with small sharp teeth or granules. Somewhat nearer to the median ridge than to the lateral 

 border the gastric region carries also a longitudinal row of acute teeth and granules ; this row 

 that appears slightly concave, with the concavity turned outward, carries anteriorly two spiniform 

 teeth behind one another, which are as large as those of the median ridge, and these teeth 

 are foliowed by two or three acute granules. 



The orbital notches are triangular, narrow gradually backward and are not subdivided 

 into two portions as in Pol. typhlops Heller. In the figure 1 C of Plate XIV of the Challenger 

 Report the inner margin of the orbital notch is divided by a prominence into two equal parts; 

 in the male from Stat. 3S this prominence is situated much more backward and the female 

 shows no tracé of it at all; this inner margin carries a few small acute granules. The rounded 

 outer angle is armed in the male with 5 or 6 slender spines of nearly equal length, in the 

 female 2 or 3 in the middle are longer than the others. The spine at the antero-lateral angle 

 of the carapace has, in Figure 1 of the Challenger Report, a quite different form than in 

 Fig. 1 C, the figure 1 is therefore probably inaccurate. In the "Siboga" specimens the spine at 

 the antero-lateral angles is distinctly larger than the following and the acute point is curved 

 inward; in both figures of the Challenger Report this spine is directed outward. 



The eye-peduncle carries on its frontal margin an acute spiniform tooth, that stands 

 twice as far distant from the outer than from the inner angle. 



The abdomen, not yet one and a half as long as the carapace measured in the middle 

 line, is a telson-length longer than the latter. In a lateral view our specimens agree very well 

 with Bate's Figure 1 P, the granules of the doublé carina of the 6 th segment are, however, 

 more conspicuous and, just behind its anterior margin, the middle line of the telson carries 4 

 or 5 prominent granules, that are wanting in the figures of the Report on the Challenger 

 Macrura. Like in the latter, the median carina of the 5 th tergum culminates, in the male, 



