1 now propose to consider the specimens from the Reef Xaifaro as the typical form of 

 Syn. fossor (Paulson), from which the variety propinqua difters by the more si en der shape of 

 the meri and propodi of the three posterior legs and by the larger number of propodal spinules. 

 In other respects the specimens collected by the "Siboga" resemble those from the 

 Reef Xaifaro, except the s m a 1 1 chela, which in the former usually also shows a more slender 

 form, though not as a rule (Table B). I will, finally, add some observations about the "Siboga" 

 specimens. In the adult female from Stat. 96 the rostrum reaches to the middle of the visible 

 part of fïrst antennular article, the lateral spines which are directed straightly forward, are a little 

 shorter, while the tips of the three spines are setose and slightly curved upward. The stylocerite 

 reaches to the 2 uJ third part, the lower spine of the basicerite almost to the middle of second 

 antennular article ; the upper spine is slightly directed upward and appears, in a lateral view, 

 almost half as long as the lower. The carpocerite extends bevond the antennular peduncle by 

 somewhat more than the length of third article, the terminal spine of the scaphocerite, thouo-h 

 much shorter than the carpocerite, just extends beyond the antennular peduncle, while the scale 

 hardly surpasses the second antennular article, which is one and a half as long as the third. 



In the male, not in the female, all the abdominal pleura terminate in a subacute, spini- 

 form tooth; this tooth occurs in the first pleura at the posterior end of the lower margin, in 

 the second a little more forward and in the following- in the middle. 



In the specimen from Stat. 96 the spinules on the upper surface of the telson are 0,36 mm. 

 long, longer than in the others; in the male from Stat. 164 they are 0,24 mm. long, in the 

 female 0,26 mm.; in the almost adult female from Stat. 282 they are 0,2 mm. long, as long 

 nearly as in the specimens from the Reef Naifaro, in which these spinules measure 0,18 mm. 

 We may therefore conclude that their length is also much variable. In the female from Stat. 96, 

 in the other specimens captured by the "Siboga" and in the male from the Reef Naifaro the 

 posterior margin surpasses but little the spiniform lateral angles, but in the female from that 

 Reef the posterior margin extends much more backward. 



In the female from Stat. 96 the merus of the large cheliped is twice as long as wide 

 and the upper margin ends in a small, sharp tooth; there is an obtuse tubercle at the distal 

 margin of the palm and another smaller one near the former. In the male from Stat. 164 the 

 merus of the large cheliped is also twice as long as wide, but the fingers are a little longer. 



In the second legs of the female from Stat. 96 the merus is 5,4-times longer than wide 

 and a little shorter than the carpus, the first segment of the carpus is 4-times as long as thick 

 and a little shorter than the sum of the following; in the female from Reef Xaifaro the merus 

 is only 4,3-times as long as wide and the first carpal segment 3,75-times longer than thick. 



As regards the following legs I wish to remark that the length of the dactylus of the 

 third legs, measured from the proximal extremity of the anterior border to the extremity of 

 the principal hook, measures in all the specimens one-fifth of the propodus; like the other joints 

 the dactyli are also a little more slender than those of the specimens from the Naifaro Reef 

 and the ventral supernumerary hook is usually a little less prominent than in the species 

 inhabiting the Maldive Archipelago. 



Eggs moderately numerous, 1 — 1,1 mm. long. 



119 



