214 



As in Syn. Gravieri the rostrum and the orbital spines are setose at their tips ; the 

 rostrum which is slightly upturned at the extremity and slightly longer than the orbital spines, 

 reaches to the distal third or fourth of the visible part of first antennular article, sometimes, 

 as in an adult female from Stat. 164, hardly beyond the middle. The orbital spines that are 

 subacute - - in an adult, ova-bearing female from Stat. 164 even rather obtuse — are much 

 broader than the rostrum, slightly convex above and their tips are a little curved inward, just 

 as in the Mergui cotypes. Telson rather elongate, proportion between its length and the width 

 of the posterior margin varying from 3 to 3,43, greatest width anteriorly twice as large as the 

 width of the posterior margin. The spinules of the upper surface are situated more backward 

 and the two pairs are situated nearer to one another than those of Syn. Gravieri, as 

 is proved by comparing the Table of measurements of both species. 



The large chela accords with my figure 61 a (1. c. 1897). In my Report of 1888 nothing 

 is said concerning the small chela, while in my paper of 1897 it is described as presenting 

 nearly the same form as in Syn. neptunus (Dana) (Dana, PI. 35, iïg. 5^). In the two cotypes 

 from Mergui this is indeed the case: in Dana's figure the proportion between the length of 

 the chela and the height of the palm appears to be 3,3, in the two Mergui specimens 3,4 and 

 3,35 and in either of them the fingers are slightly shorter than the palm. Novv it is a remarkable 

 fact that in the specimens collected by the "Siboga" the smaller chela shows a somewhat 

 more slender shape, the proportion between the total length and the height of the palm 

 varying between 3,8 and 4,33; the fingers are, in adult specimens, a little shorter, as 

 long or slightly longer than the palm. The palm therefore usually appears a little 

 more slender than in the cotypes from the Mergui- Archipelago, but in the adult male from 

 Stat. 99 its shape is the same, the proportion between the length of the palm and its height 

 being 1,8, in the Mergui specimens 1,77 and 1,7: it is therefore obvious that the stouter form 

 of this chela in the specimens from the Mergui-Archipelago is only an individual feature — 

 and that the specimens taken by the "Siboga" indeed belong to Syn. neomcris. 



The 2 nd legs resemble those of Syn. Gravieri. The first carpal segment is slender, 6- 

 times as long as thick, and longer than the following segments taken together : in very young 

 specimens, as in N° 6 of the Table of measurements, the first segment is stouter and slightly 

 shorter than the following taken together. The number of spinules with which the meri of the third 

 legs are armed, 3 in very young specimens, amounts to 4, 5, 6, even to 8 in larger and adult 

 individuals ; the meri of the fourth legs bear 2, 3 or 4 spinules, in young specimens only one. 

 The dorsal hook of the dactylus of the third legs measures one-third the length of the principal 

 one, its thickness is usually a little less than one-third, sometimes almost one-fourth that of the 

 other; the dactyli of the fourth legs resemble those of the third. As regards these legs I refer 

 to the Tables B and C of measurements. 



Table A. 



Proportion between length of telson and width of 



posterior margin 



Proportion between the greatest width and that of 



posterior margin 



1 U V . 



3>o: 



212 



82 



