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rim, obliquely running from the anterior angle of the quadrate buccal cavern to the base of 

 the cheliped; this rim is cut into three lobules, the anterior of which, near the angle of the 

 buccal cavern, being the smallest, and the next the largest; the inferior part of the ptery- 

 gostomial region, like the rim itself, and the upper surface of the external maxillipeds are beset 

 with short hairs. The external maxillipeds completely close the buccal cavern ; the merus is 

 roughly triangular, shorter than the ischium, with the carpus inserted near the antero-external 

 angle ; the exognath is wholly exposed ^), reaching nearly as far as the merus. 



The abdomen of the cf is broadly triangular, reaching forward nearly to the anterior 

 margin of the sternum, the penultimate segment is somewhat shorter than the two preceding 

 segments and the terminal segment; the latter is triangular, about as long as broad at the 

 base, and with the tip rounded. 



The chelipeds of the cT are much longer than those of the 9 and twice the length of 

 the carapace; the meropodite is slender, widening distally, rounded, and the upper border is 

 somewhat produced above the carpal joint; the palm is much swollen, quite smooth and 

 hairjess, about i^j^ times the length of the fingers; the latter are straight, acute at apex, not 

 gaping, with the inner margins finely serrated and a quadrangular tooth quite near the base 

 of the mobile finger. In the 9 the whole cheliped is shorter and weaker; the fingers are much 

 longer, nearly equalling the length of the palm, finely serrated at inner margin and without 

 larger tooth; the tips are slightly spooned, and this difference between the two .sexes seems 

 to be characteristic of the genus. 



The ambulatory legs of the cf are very slender and elongate, the second pair, which 

 is the longest, being 2^l„ times the length of the carapace, smooth and hairless, except the 

 dactyli; the anterior margin of the mero- and carpopodite is produced distally, and the long, 

 falcate, slightly curved dactyli are nearly as long as the preceding joints; the inner margin of 

 the dactyli is hairy all along and near the tip are two diverging denticles. In the 9 (save in 

 the smallest specimen) the legs are much shorter, the dactyli are broader, more strongly curved, 

 especially so in the case of the posterior legs -), but armed in the same way (fig. 4.C). 



It is remarkable, that all the 9i though the largest is twice as broad as the smallest, 

 are egg-bearing. 



Dimensions in mm. : 



Length of carapace 



Breadth of carapace 



Length of cheliped 



Length of palm 



Length of mobile finger 



Length of penultimate pair of legs . . 



N'^ I and 3 are from Ambon, n" 2 is from Gisser (east of Ceram). 



1) Al.coCK (I.e. p. 385) says that this exognath is completely hidden both in the genera Elaiitena and Trigotioplax. 



2) Whether these dactyli are also more curved in the (^ I could not make out, as in both my ^ specimens the posterior pair 

 of legs is wanting. 



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